PATENT ABSTRACT
An electro-optic integrated circuit including an integrated circuit substrate, at least one optical signal providing element and at least one discrete reflecting optical element, mounted onto the integrated circuit substrate, cooperating with the at least one optical signal providing element and being operative to direct light from the at least one optical signal providing element. An electro-optic integrated circuit including an integrated circuit substrate, at least one optical signal receiving element and at least one discrete reflecting optical element, mounted onto the integrated circuit substrate, cooperating with the at least one optical signal receiving element and being operative to direct light to the at least one optical signal receiving element.

PATENT DESCRIPTION
REFERENCE TO CO-PENDING APPLICATIONS  
       [0001]     Applicant hereby claims priority of U.S. Provisional Patent Application Ser. No. 60/373,415, filed on Apr. 16, 2002, entitled “Electro-Optic Integrated Circuits and Methods for the Production Thereof”, U.S. patent application Ser. No. 10/314,088, filed Dec. 6, 2002, entitled “Electro-Optic Integrated Circuits with Connectors and Methods for the Production Thereof” and U.S. Provisional Patent Application Ser. No. 60/442,948, filed on Jan. 27, 2003, entitled “Direct Optical Connection”. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to high speed integrated circuits interconnection, electro-optic integrated circuits and methods for the production thereof generally and more particularly to wafer level manufacture of chip level electro-optic integrated circuits with integrated optical connectors and optical interconnections means to transfer data between semiconductor integrated circuits.  
       BACKGROUND OF THE INVENTION  
       [0003]     The following U.S. patents of the present inventor represent the current state of the art:  
         [0004]     U.S. Pat. Nos. 6,117,707; 6,040,235; 6,022,758; 5,980,663; 5,716,759; 5,547,906 and 5,455,455.  
         [0005]     The following U.S. patents represent the current state of the art relevant to stud bump mounting of electrical circuits:  
         [0006]     U.S. Pat. Nos. 6,214,642; 6,103,551; 5,844,320; 5,641,996; 5,550,408 and 5,436,503.  
         [0007]     Additionally, the following patents are believed to represent the current state of the art:  
         [0008]     U.S. Pat. Nos. 4,168,883; 4,351,051; 4,386,821; 4,399,541; 4,615,031; 4,810,053; 4,988,159; 4,989,930; 4,989,943; 5,044,720; 5,231,686; 5,841,591; 6,052,498; 6,058,228; 6,234,688; 5,886,971; 5,912,872; 5,933,551; 6,061,169; 6,071,652; 6,096,155; 6,104,690; 6,235,141; 6,295,156; 5,771,218 and 5,872,762.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention seeks to provide improved optical interconnections means to transfer high speed data between semiconductor integrated circuits, electro-optic integrated circuits and methods for production thereof.  
         [0010]     There is thus provided, in accordance with a preferred embodiment of the present invention, an electro-optic integrated circuit including an integrated circuit substrate, at least one optical signal providing element and at least one discrete reflecting optical element, mounted onto the integrated circuit substrate, cooperating with the at least one optical signal providing element and being operative to direct light from the at least one optical signal providing element.  
         [0011]     There is also provided, in accordance with another preferred embodiment of the present invention, an electro-optic integrated circuit including an integrated circuit substrate, at least one optical signal receiving element and at least one discrete reflecting optical element mounted onto the integrated circuit substrate and cooperating with the at least one optical signal receiving element and being operative to direct light to the at least one optical signal receiving element.  
         [0012]     There is further provided, in accordance with yet another preferred embodiment of the present invention, an electro-optic integrated circuit including an integrated circuit substrate defining a planar surface, at least one optical signal providing element and at least one reflecting optical element having an optical axis which is neither parallel nor perpendicular to the planar surface, the element cooperating with the at least one optical signal providing element and being operative to direct light from the at least one optical signal providing element.  
         [0013]     There is also provided, in accordance with still another preferred embodiment of the present invention, an electro-optic integrated circuit including an integrated circuit substrate defining a planar surface, at least one optical signal receiving element and at least one reflecting optical element having an optical axis which is neither parallel nor perpendicular to the planar surface, the element cooperating with the at least one optical signal receiving element and being operative to direct light to the at least one optical signal receiving element.  
         [0014]     There is further provided, in accordance with another preferred embodiment of the present invention, a method for producing an electro-optic integrated circuit including providing an integrated circuit substrate, mounting at least one optical signal providing element onto the integrated circuit substrate, mounting at least one optical signal receiving element onto the integrated circuit substrate and providing optical alignment, between the at least one optical signal providing element and the at least one optical signal receiving element, subsequent to mounting thereof, by suitable positioning along an optical path extending there between, an intermediate optical element and fixing the intermediate optical element to the integrated circuit substrate.  
         [0015]     In accordance with a further preferred embodiment of the present invention, the intermediate optical element, when fixed to the substrate, has an optical axis, which is neither parallel nor perpendicular to a planar surface of the integrated circuit substrate.  
         [0016]     There is also provided, in accordance with yet another preferred embodiment of the present invention, a method for producing an electro-optic integrated circuit including providing an integrated circuit substrate, mounting at least one optical signal providing element on the integrated circuit substrate and mounting at least one discrete reflecting optical element onto the integrated circuit substrate to cooperate with the at least one optical signal providing element and to direct light from the at least one optical signal providing element.  
         [0017]     There is further provided, in accordance with still another preferred embodiment of the present invention, a method for producing an electro-optic integrated circuit including providing an integrated circuit substrate, mounting at least one optical signal receiving element on the integrated circuit substrate and mounting at least one discrete reflecting optical element onto the integrated circuit substrate to cooperate with the at least one optical signal receiving element and to direct light to the at least one optical signal receiving element.  
         [0018]     There is also provided, in accordance with another preferred embodiment of the present invention, a method for producing an electro-optic integrated circuit including providing an integrated circuit substrate defining a planar surface, mounting at least one optical signal providing element on the integrated circuit substrate and mounting at least one reflecting optical element onto the integrated circuit substrate to cooperate with the at least one optical signal providing element and to direct light from the at least one optical signal providing element, wherein an optical axis of the at least one reflecting optical element is neither parallel nor perpendicular to the planar surface.  
         [0019]     There is further provided, in accordance with yet another preferred embodiment of the present invention, a method for producing an electro-optic integrated circuit including providing an integrated circuit substrate defining a planar surface, mounting at least one optical signal receiving element on the integrated circuit substrate and mounting at least one reflecting optical element onto the integrated circuit substrate to cooperate with the at least one optical signal receiving element and to direct light to the at least one optical signal receiving element, wherein an optical axis of the at least one reflecting optical element is neither parallel nor perpendicular to the planar surface.  
         [0020]     In accordance with a preferred embodiment of the present invention, the at least one optical element includes a flat reflective surface. Additionally, the at least one optical element includes a concave mirror. Alternatively, the at least one optical element includes a partially flat and partially concave mirror. Additionally, the partially concave mirror includes a mirror with multiple concave reflective surfaces.  
         [0021]     In accordance with another preferred embodiment, the at least one optical element includes a reflective grating. Additionally, the at least one optical element includes reflective elements formed on opposite surfaces of an optical substrate. Preferably, at least one of the reflective elements includes a flat reflective surface. Alternatively, at least one of the reflective elements includes a concave mirror. Alternatively or additionally, at least one of the reflective elements includes a partially flat and partially concave mirror. Additionally, the mirror includes a mirror with multiple concave reflective surfaces. Alternatively, at least one of the reflective elements includes a reflective grating.  
         [0022]     Preferably, the at least one optical element is operative to focus light received from the optical signal providing element. Alternatively, the at least one optical element is operative to collimate light received from the optical signal providing element. In accordance with another preferred embodiment, the at least one optical element is operative to focus at least one of multiple colors of light received from the optical signal providing element. Additionally or alternatively, the at least one optical element is operative to collimate at least one of multiple colors of light received from the optical signal providing element. In accordance with another preferred embodiment, the at least one optical element is operative to enhance the optical properties of light received from the optical signal providing element.  
         [0023]     In accordance with a preferred embodiment, the optical signal-providing element includes an optical fiber. Alternatively, the optical signal-providing element includes a laser diode. Additionally or alternatively, the optical signal-providing element includes a waveguide. In accordance with another preferred embodiment, the optical signal-providing element includes an array waveguide grating. Alternatively, the optical signal-providing element includes a semiconductor optical amplifier.  
         [0024]     Preferably, the optical signal-providing element is operative to convert an electrical signal to an optical signal. Alternatively, the optical signal-providing element is operative to transmit an optical signal. Additionally, the optical signal-providing element also includes an optical signal-receiving element. In accordance with another preferred embodiment, the optical signal-providing element is operative to generate an optical signal.  
         [0025]     In accordance with a preferred embodiment of the present invention, the integrated circuit substrate includes Silicon, Silicon Germanium, and gallium arsenide. Alternatively, the integrated circuit substrate includes indium phosphide.  
         [0026]     In accordance with another preferred embodiment of the present invention, the integrated circuit includes at least one optical signal providing element and at least one optical element receiving element, the at least one discrete reflecting optical element cooperating with the at least one optical signal providing element and the at least one optical signal receiving element and being operative to direct light from the at least one signal providing element to the at least one optical signal receiving element.  
         [0027]     Preferably, the at least one optical signal receiving element includes an optical fiber. Alternatively, the at least one optical signal receiving element includes a laser diode. Additionally or alternatively, the at least one optical signal receiving element includes a diode detector.  
         [0028]     In accordance with a preferred embodiment of the present invention, the at least one optical signal receiving element is operative to convert an optical signal to an electrical signal. Additionally, the at least one optical signal receiving element is operative to transmit an optical signal. Alternatively, the at least one optical signal receiving element also includes an optical signal providing element.  
         [0029]     Preferably, the at least one reflecting optical element is operative to focus light received by the optical signal-receiving element. Alternatively, the at least one reflecting optical element is operative to collimate light received by the optical signal-receiving element. In accordance with another preferred embodiment, the at least one reflecting optical element is operative to focus at least one of multiple colors of light received by the optical signal-receiving element. Additionally or alternatively, the at least one reflecting optical element is operative to collimate at least one of multiple colors of light received by the optical signal receiving element. In accordance with another preferred embodiment, the at least one reflecting optical element is operative to enhance the optical properties of light received by the optical signal-receiving element.  
         [0030]     There is also provided, in accordance with another preferred embodiment of the present invention, an integrated circuit including a first integrated circuit substrate having first and second planar surfaces, the first planar surface having first electrical circuitry formed thereon and the second planar surface having formed therein at least one recess, filling the recess with clear material to form an optical via through the semiconductor substrate, and at least one second integrated circuit substrate having second electrical circuitry formed thereon, the at least one second integrated circuit substrate being located at least partially above the at least one recess, the second electrical circuitry communicating with the first electrical circuitry.  
         [0031]     There is also provided, in accordance with another preferred embodiment of the present invention, an integrated circuit including a first integrated circuit substrate having first and second planar surfaces, the first planar surface having first electrical circuitry formed thereon and the second planar surface having formed therein at least one recess, filling the recess with clear material to form an optical via through the semiconductor substrate, and at least one second integrated circuit substrate having second electrical circuitry formed thereon, the at least one second integrated circuit substrate being located at least partially above the at least one recess, the second electrical circuitry communicating with the first electrical circuitry.  
         [0032]     Preferably, the first electrical circuitry includes electronic components and optical waveguides. Additionally, the second electrical circuitry includes electro-optic components. In accordance with a preferred embodiment, the second electrical circuitry communicating with the first electrical circuitry optical waveguides includes communicating via an optical communication path. Additionally, the optical communication path includes optical coupling through free space.  
         [0033]     There is also provided, in accordance with still another preferred embodiment of the present invention, an integrated circuit including a first integrated circuit substrate having first and second planar surfaces, the first planar surface having first electrical circuitry formed thereon and the second planar surface having formed therein at least one recess and at least one second substrate, the at least one second substrate being located at least partially above the at least one recess, the second substrate containing at least one element communicating with the first electrical circuitry.  
         [0034]     There is further provided, in accordance with another preferred embodiment, an integrated circuit including a first integrated circuit substrate, having electrical circuitry formed thereon and having formed therein at least one recess and at least one second substrate, the at least one second substrate being located at least partially above the at least one recess, the second substrate containing at least one element communicating with the electrical circuitry.  
         [0035]     There is also provided, in accordance with yet another preferred embodiment, a method for producing an integrated circuit including providing a first integrated circuit substrate, with first and second planar surfaces, forming first electrical circuitry on the first planar surface, forming at least one recess in the second planar surface, providing at least one second substrate and locating the at least one second substrate at least partially above the at least one recess, the second substrate containing at least one element communicating with the first electrical circuitry.  
         [0036]     There is further provided, in accordance with still another preferred embodiment, a method for producing an integrated circuit including providing a first integrated circuit substrate, forming electrical circuitry on the first substrate, forming at least one recess in the first substrate, providing at least one second substrate and locating the at least one second substrate at least partially above the at least one recess, the second substrate containing at least one element communicating with the electrical circuitry.  
         [0037]     In accordance with a preferred embodiment, the first electrical circuitry includes electronic components. Additionally, the at least one element includes electro-optic components. Preferably, the at least one element communicating with the first electrical circuitry includes communicating via an optical communication path. Additionally, the optical communication path includes optical coupling through free space.  
         [0038]     There is yet further provided, in accordance with another preferred embodiment of the present invention, an integrated circuit including a silicon integrated circuit substrate having electrical signal processing circuitry formed thereon and at least one discrete optical element mounted thereon, the electrical signal processing circuitry including an electrical signal input and an electrical signal output and the at least one discrete optical element including an optical input and an optical output.  
         [0039]     There is also provided, in accordance with yet another preferred embodiment of the present invention, a method for producing an integrated circuit including providing a silicon integrated circuit substrate, forming electrical signal processing circuitry on the substrate and mounting at least one discrete optical element on the substrate, the electrical signal processing circuitry including an electrical signal input and an electrical signal output and the at least one discrete optical element including an optical input and an optical output.  
         [0040]     Preferably, the optical element is operative to convert the electrical signal output into the optical input. Alternatively, the electrical signal processing circuitry is operative to convert the optical output into the electrical signal input. In accordance with another preferred embodiment, the electrical signal processing circuitry and the discrete optical element are located on a single planar surface of the substrate. Alternatively, the electrical signal processing circuitry and the discrete optical element are located on different planar surfaces of the substrate.  
         [0041]     There is yet further provided, in accordance with another preferred embodiment of the present invention, an integrated circuit including a silicon integrated circuit substrate having electrical signal processing circuitry formed thereon and at least one discrete optical element mounted thereon, the electrical signal processing circuitry including an electrical signal input and an electrical signal output and the at least one discrete optical element including an optical input and an optical output, the integrated circuit including at least one optical connector including a plurality of optical elements defining at least one optical input path and at least one optical output path.  
         [0042]     There is further provided in accordance with another preferred embodiment of the present invention, a method for producing an integrated circuit including a silicon integrated circuit substrate having electrical signal processing circuitry formed thereon and at least one discrete optical element mounted thereon, the electrical signal processing circuitry including an electrical signal input and an electrical signal output and the at least one discrete optical element including an optical input and an optical output, the integrated circuit also including at least one optical connector including a plurality of optical elements defining at least one optical input path and at least one optical output path an optical connector including providing a plurality of optical elements, defining at least one optical input path through at least one of the plurality of optical elements and defining at least one optical output path through at least one of the plurality of optical elements.  
         [0043]     Preferably, at least one of the plurality of optical elements includes a flat reflective surface. Additionally, at least one of the plurality of optical elements includes a concave mirror. Additionally or alternatively, at least one of the plurality of optical elements includes a partially flat and partially concave mirror. Alternatively, at least one of the plurality of optical elements includes a mirror with multiple concave reflective surfaces. Additionally or alternatively, at least one of the plurality of optical elements includes a reflective grating. Additionally, at least one of the plurality of optical elements includes reflective elements formed on opposite surfaces of an optical substrate.  
         [0044]     In accordance with a preferred embodiment, at least one of the plurality of optical elements is operative to focus light. Alternatively, at least one of the plurality of optical elements is operative to collimate light. Additionally, at least one of the plurality of optical elements is operative to focus at least one of multiple colors of light. Additionally or alternatively, at least one of the plurality of optical elements is operative to collimate at least one of multiple colors of light. Alternatively, at least one of the plurality of optical elements is operative to enhance the optical properties of light.  
         [0045]     Preferably, at least one of the plurality of optical elements includes an optical fiber. Additionally, at least one of the plurality of optical elements includes a laser diode. Alternatively, at least one of the plurality of optical elements includes a diode detector.  
         [0046]     There is further provided in accordance with still another preferred embodiment of the present invention an optical reflector including an optical substrate, at least one microlens formed on a surface of the optical substrate and a first reflective surface formed over the at least one microlens.  
         [0047]     There is still further provided in accordance with yet another preferred embodiment of the present invention a method for producing an optical reflector including providing an optical substrate, forming at least one microlens on a surface of the optical substrate, coating the at least one microlens with a reflective material and dicing the substrate.  
         [0048]     Preferably, the first reflective surface is also formed over at least a portion of the surface of the optical substrate. Alternatively, at least a portion of the first reflective surface includes a grating. Preferably, the first reflective surface includes aluminum.  
         [0049]     In accordance with another preferred embodiment, the optical reflector also includes at least one second reflective surface formed on at least a portion of an opposite surface of the substrate. Additionally, at least a portion of the second reflective surface includes a grating. Preferably, the second reflective surface includes aluminum.  
         [0050]     In accordance with yet another preferred embodiment, the optical reflector also includes a notch formed in the opposite surface of the substrate.  
         [0051]     Preferably, the at least one microlens includes photoresist. Alternatively, the at least one microlens is formed by photolithography and thermal reflow forming. Additionally, the at least one microlens is formed by photolithography using a grey scale mask forming. Alternatively, the at least one microlens is formed by jet printing formation.  
         [0052]     In accordance with still another preferred embodiment, the at least one microlens has an index of refraction which is identical to that of the optical substrate. Alternatively, the at least one microlens has an index of refraction which closely approximates that of the optical substrate.  
         [0053]     There is also provided in accordance with another preferred embodiment of the present invention a packaged electro-optical integrated circuit having integrally formed therein an optical connector to an optical fiber.  
         [0054]     Preferably, the optical connector includes a pair of elongate locating pin sockets formed over a silicon substrate of the integrated circuit, and extending generally parallel to a surface thereof. Additionally, the optical connector includes a linear array of optical fiber ends arranged to have abutment surfaces generally coplanar with an edge of the packaged electro-optical integrated circuit.  
         [0055]     There is further provided in accordance with yet another preferred embodiment of the present invention a method for wafer scale production of an electro-optic circuit having integrally formed therein an optical connector and electrical connections including wafer scale formation of a multiplicity of electro-optical circuits onto a substrate, wafer scale provision of at least one optical waveguide on the substrate, wafer scale mounting of at least one integrated circuit component onto the substrate, wafer scale formation of at least one optical pathway providing an optical connection between the at least one integrated circuit component and the at least one optical waveguide, wafer scale formation of at least one mechanical alignment bore on the substrate, wafer scale formation of at least one packaging layer over at least one surface of the substrate and thereafter, dicing of the substrate to define a multiplicity of electro-optic circuits, each having integrally formed therein an optical connector.  
         [0056]     Preferably, an end of the at least one optical waveguide defines an optical connector interface. Additionally, the substrate includes a silicon substrate having formed thereon a multiplicity of integrated circuits.  
         [0057]     There is still further provided in accordance with still another preferred embodiment of the present invention a method of mounting an integrated circuit onto an electrical circuit including forming an integrated circuit with a multiplicity of electrical connection pads which generally lie along a mounting surface of the integrated circuit, forming an electrical circuit with a multiplicity of electrical connection contacts which generally protrude from a mounting surface of the electrical circuit and employing at least a conductive adhesive to electrically and mechanically join the multiplicity of electrical connection pads to the multiplicity of electrical connection contacts.  
         [0058]     Preferably, the integrated circuit is an electro-optical circuit, and the method also includes providing an optically transparent underfill layer intermediate the mounting surface of the integrated circuit and the mounting surface of the electrical circuit.  
         [0059]     There is also provided in accordance with another preferred embodiment of the present invention a method for wafer scale production of an electro-optical circuit including wafer scale formation of a multiplicity of electro-optical circuits onto an active surface of a substrate and wafer scale provision of at least one optical via on the substrate.  
         [0060]     Preferably, the wafer scale provision of the at least one optical via includes etching the substrate on a non-active surface thereof at a location opposite a region of the active surface generally free of circuitry, thereby to define at least one cavity whose bottom surface is translucent and filling the at least one cavity with a transparent material.  
         [0061]     Additionally, the method also includes attaching a semiconductor element in optical engagement with the at least one optical via.  
         [0062]     In accordance with yet another preferred embodiment of the present invention the transparent material has an index of refraction similar to that employed along at least one optical path in the electro-optical circuit communicating therewith.  
         [0063]     There is further provided in accordance with still another preferred embodiment of the present invention a method for wafer level production of a electro-optical circuit including forming electrical circuitry on a first side of a wafer, forming an optical assembly on a second side of the wafer and forming an optical connection between the first and second sides of the wafer, through the wafer, thereby providing optical communication between the electrical circuitry and the optical assembly through the wafer.  
         [0064]     Preferably, the method also includes dicing the wafer to define a multiplicity of integrated circuits each having formed thereon electrical circuitry on a first side of the integrated circuit, an optical assembly on a second side of the integrated circuit and an optical connection between the first and second sides of the integrated circuit, thereby providing optical communication between the electrical circuitry and the optical assembly.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0065]     The present invention will be appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:  
         [0066]      FIGS. 1A, 1B ,  1 C,  1 D and  1 E are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with a preferred embodiment of the present invention;  
         [0067]      FIGS. 2A, 2B ,  2 C, and  2 D are simplified sectional illustrations of further stages in the production of the electro-optic integrated circuit referenced in  FIGS. 1A-1E ;  
         [0068]      FIG. 3  is an enlarged simplified optical illustration of a portion of  FIG. 2D ;  
         [0069]      FIGS. 4A, 4B ,  4 C,  4 D and  4 E are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with another preferred embodiment of the present invention;  
         [0070]      FIGS. 5A, 5B ,  5 C and  5 D are simplified sectional illustrations of further stages in the production of the electro-optic integrated circuit referenced in  FIGS. 4A-4E ;  
         [0071]      FIGS. 6A, 6B  and  6 C are enlarged simplified optical illustrations of a portion of  FIG. 5D  in accordance with preferred embodiments of the present invention;  
         [0072]      FIG. 7  is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention;  
         [0073]      FIGS. 8A, 8B  and  8 C are enlarged simplified optical illustrations of a portion of  FIG. 7  in accordance with other embodiments of the present invention;  
         [0074]      FIGS. 9A, 9B ,  9 C,  9 D and  9 E are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention;  
         [0075]      FIGS. 10A, 10B ,  10 C and  10 D are simplified sectional illustrations of further stages in the production of the electro-optic integrated circuit referenced in FIGS.  9 A- 9 E;  
         [0076]      FIGS. 11A, 11B  and  11 C are enlarged simplified optical illustrations of a portion of  FIG. 10D  in accordance with preferred embodiments of the present invention;  
         [0077]      FIG. 12  is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention;  
         [0078]      FIGS. 13A, 13B  and  13 C are enlarged simplified optical illustrations of a portion of  FIG. 12  in accordance with further preferred embodiments of the present invention;  
         [0079]      FIGS. 14A, 14B ,  14 C and  14 D are simplified sectional illustrations of stages in the production an electro-optic integrated circuit in accordance with another embodiment of the present invention;  
         [0080]      FIGS. 15A, 15B  and  15 C are simplified optical illustrations of  FIG. 14D  in accordance with preferred embodiments of the present invention;  
         [0081]      FIG. 16  is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention;  
         [0082]      FIGS. 17A, 17B  and  17 C are enlarged simplified optical illustrations of a portion of  FIG. 16  in accordance with further embodiments of the present invention;  
         [0083]      FIGS. 18A, 18B ,  18 C and  18 D are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 4A-6C  in accordance with one embodiment of the present invention;  
         [0084]      FIGS. 19A, 19B ,  19 C,  19 D and  19 E are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-6C  in accordance with another embodiment of the present invention;  
         [0085]      FIGS. 20A, 20B ,  20 C,  20 D,  20 E and  20 F are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 9A-17C  in accordance with yet another embodiment of the present invention;  
         [0086]      FIGS. 21A, 21B ,  21 C,  21 D,  21 E and  21 F are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-17C  in accordance with still another embodiment of the present invention;  
         [0087]      FIGS. 22A, 22B ,  22 C,  22 D,  22 E,  22 F and  22 G are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-8C  in accordance with a further embodiment of the present invention;  
         [0088]      FIGS. 23A, 23B ,  23 C,  23 D,  23 E,  23 F and  23 G are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 9A-17C  in accordance with yet a further embodiment of the present invention;  
         [0089]      FIGS. 24A, 24B ,  24 C,  24 D,  24 E,  24 F and  24 G are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-17C  in accordance with a still further embodiment of the present invention;  
         [0090]      FIGS. 25A, 25B ,  25 C and  25 D are simplified illustrations of multiple stages in the production of a multi-chip module in accordance with a preferred embodiment of the present invention;  
         [0091]      FIG. 26  is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including a laser light source;  
         [0092]      FIG. 27  is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including an optical detector;  
         [0093]      FIG. 28  is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including an electrical element;  
         [0094]      FIG. 29  is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including multiple elements located in multiple recesses formed within a substrate;  
         [0095]      FIG. 30  is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including multiple stacked elements located in recesses formed within substrates;  
         [0096]      FIGS. 31A, 31B ,  31 C and  31 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with a preferred embodiment of the present invention;  
         [0097]      FIG. 32  is an enlarged simplified optical illustration of a portion of  FIG. 31D ;  
         [0098]      FIGS. 33A, 33B ,  33 C and  33 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with another preferred embodiment of the present invention;  
         [0099]      FIG. 34  is an enlarged simplified optical illustration of a portion of  FIG. 33D ;  
         [0100]      FIGS. 35A, 35B ,  35 C and  35 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with a preferred embodiment of the present invention;  
         [0101]      FIG. 36  is an enlarged simplified optical illustration of a portion of  FIG. 35D ;  
         [0102]      FIGS. 37A, 37B ,  37 C and  37 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with another preferred embodiment of the present invention;  
         [0103]      FIG. 38  is an enlarged simplified optical illustration of a portion of  FIG. 37D ;  
         [0104]      FIGS. 39A, 39B ,  39 C and  39 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with yet another preferred embodiment of the present invention;  
         [0105]      FIG. 40  is a simplified optical illustration of  FIG. 39D ;  
         [0106]      FIGS. 41A, 41B ,  41 C and  41 D are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with still another preferred embodiment of the present invention;  
         [0107]      FIG. 42  is a simplified optical illustration of  FIG. 41D ;  
         [0108]      FIG. 43  is a simplified optical illustration of optical communication between connectors of the types shown in  FIGS. 40 and 42 ;  
         [0109]      FIG. 44  is a simplified optical illustration of optical communication between two connectors of the type shown in  FIG. 40 ;  
         [0110]      FIG. 45  is a simplified optical illustration of optical communication between two connectors of the type shown in  FIG. 42 ;  
         [0111]      FIGS. 46A, 46B ,  46 C and  46 D are simplified illustrations of stages in the production of an electro-optic integrated circuit in accordance with another preferred embodiment of the present invention;  
         [0112]      FIG. 47  is an enlarged simplified optical illustration of a portion of FIG.  46 D;  
         [0113]      FIG. 48  is a simplified optical illustration of optical communication between an electro-optic integrated circuit and an electro-optic integrated circuit in accordance with another preferred embodiment of the present invention;  
         [0114]      FIG. 49  is a simplified optical illustration of optical communication between an optic integrated circuit and an electro-optic integrated circuit in accordance with a preferred embodiment of the present invention;  
         [0115]      FIGS. 50A, 50B ,  50 C,  50 D and  50 E are simplified pictorial illustrations of stages in the production of an electro-optic integrated circuit constructed and operative in accordance with still another preferred embodiment of the present invention;  
         [0116]      FIG. 51  is a simplified functional illustration of a preferred embodiment of the structure of  FIG. 50E ;  
         [0117]      FIGS. 52A and 52B  are simplified pictorial illustrations of a packaged electro-optic circuit having integrally formed therein an optical connector and electrical connections, alone and in conjunction with a conventional optical connector;  
         [0118]      FIGS. 53A, 53B ,  53 C,  53 D,  53 E and  53 F are simplified pictorial and sectional illustrations of a first plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B ;  
         [0119]      FIGS. 54A, 54B ,  54 C,  54 D,  54 E,  54 F,  54 G,  54 H,  541  and  54 J are simplified pictorial and sectional illustrations of a second plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B ;  
         [0120]      FIGS. 55A, 55B ,  55 C and  55 D are simplified pictorial and sectional illustrations of a third plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B ;  
         [0121]      FIGS. 56A, 56B  and  56 C are enlarged simplified optical illustrations of a portion of  FIG. 55D  in accordance with various preferred embodiments of the present invention;  
         [0122]      FIG. 57  is a simplified sectional illustration of an electro-optic circuit constructed and operative in accordance with another preferred embodiment of the present invention;  
         [0123]      FIGS. 58A, 58B  and  58 C are enlarged simplified optical illustrations of a portion of  FIG. 57  in accordance with various other preferred embodiments of the present invention;  
         [0124]      FIG. 59  is a simplified pictorial illustration corresponding to sectional illustration  55 D;  
         [0125]      FIGS. 60A, 60B ,  60 C,  60 D,  60 E and  60 F are simplified pictorial and sectional illustrations of a fourth plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B ; and  
         [0126]      FIG. 61  is a simplified illustration of incorporation of packaged electro-optic circuits of the type shown in  FIGS. 52A and 52B  as parts of a larger electrical circuit.  
         [0127]      FIG. 62  is a simplified pictorial illustration of an initial stage in the production of an electro-optic integrated circuit constructed and operative in accordance with a preferred embodiment of the present invention;  
         [0128]      FIGS. 63A, 63B ,  63 C,  63 D and  63 E are simplified sectional illustrations of further stages in the production of the electro-optic integrated circuit of  FIG. 62 ;  
         [0129]      FIG. 64  is a simplified illustration of an integrated circuit module of the type referenced in  FIGS. 63A-63E , including a laser light source;  
         [0130]      FIG. 65  is a simplified illustration of an integrated circuit module of the type referenced in  FIGS. 63A-63E , including an optical detector;  
         [0131]      FIG. 66  is a simplified illustration of an integrated circuit module of the type referenced in  FIGS. 63A-63E , including multiple elements located in multiple recesses formed within a substrate;  
         [0132]      FIGS. 67A, 67B ,  67 C and  67 D are simplified pictorial illustrations of additional stages in the production of an electro-optic integrated circuit constructed and operative in accordance with the preferred embodiment of the present invention;  
         [0133]      FIGS. 68A, 68B ,  68 C and  68 D are simplified sectional illustrations of additional stages in the production of an electro-optic integrated circuit referenced in  FIGS. 67A-67D .  
         [0134]      FIGS. 69A, 69B  and  69 C are enlarged simplified optical illustrations of a portion of  FIG. 68D  in accordance with a preferred embodiments of the present invention;  
         [0135]      FIG. 70  is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention;  
         [0136]      FIGS. 71A, 71B  and  71 C are enlarged simplified optical illustrations of a portion of  FIG. 70  in accordance with other embodiments of the present invention;  
         [0137]      FIGS. 72A, 72B ,  72 C,  72 D and  72 E are simplified pictorial illustrations of stages in the production of an electro-optic integrated circuit constructed and operative in accordance with still another preferred embodiment of the present invention;  
         [0138]      FIG. 73  is a simplified functional illustration of a preferred embodiment of the structure of  FIG. 72E ;  
         [0139]      FIGS. 74A, 74B ,  74 C,  74 D and  74 E are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with different embodiments of the present invention;  
         [0140]      FIGS. 75A, 75B ,  75 C,  75 D,  75 E and  75 F are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with other embodiments of the present invention;  
         [0141]      FIGS. 76A, 76B ,  76 C,  76 D,  76 E,  76 F and  76 G are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with yet other embodiments of the present invention;  
         [0142]      FIGS. 77A, 77B ,  77 C,  77 D,  77 E,  77 F and  77 G are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with still another embodiment of the present invention;  
         [0143]      FIGS. 78A, 78B ,  78 C,  78 D,  78 E,  78 F,  78 G and  78 H are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with a further embodiment of the present invention;  
         [0144]      FIGS. 79A, 79B ,  79 C,  79 D,  79 E,  79 F,  79 G and  79 H are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with yet a further embodiment of the present invention;  
         [0145]      FIGS. 80A, 80B ,  80 C,  80 D,  80 E,  80 F,  80 G and  80 H are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with still a further embodiment of the present invention;  
         [0146]      FIGS. 81A and 81B  are simplified pictorial illustrations of a packaged electro-optic circuit having integrally formed therein an optical connector and electrical connections, alone and in conjunction with a conventional optical connector;  
         [0147]      FIGS. 82A, 82B ,  82 C,  82 D,  82 E,  82 F and  82 G are simplified pictorial and sectional illustrations of a plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B ;  
         [0148]      FIGS. 83A, 83B ,  83 C,  83 D and  83 E are simplified pictorial and sectional illustrations of a further plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B ;  
         [0149]      FIG. 84  is a simplified pictorial illustration corresponding to sectional illustration  68 B;  
         [0150]      FIG. 85  is a simplified pictorial illustration corresponding to sectional illustrations  68 C,  68 D and  70 ;  
         [0151]      FIGS. 86A, 86B ,  86 C,  86 D,  86 E and  86 F are simplified pictorial and sectional illustrations of a further plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B ; and  
         [0152]      FIG. 87  is a simplified illustration of incorporation of packaged electro-optic circuits of the type shown in  FIGS. 81A and 81B  as parts of a larger electrical circuit.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0153]     Reference is now made to  FIGS. 1A, 1B ,  1 C,  1 D and  1 E, which are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with a preferred embodiment of the present invention. As seen in  FIG. 1A , one or more electrical circuits  100  are preferably formed onto a first surface  102  of a substrate  104 , preferably a silicon substrate or a substrate that is generally transparent to light within at least part of the wavelength range of 600-1650 nm, typically of thickness between 200-800 microns. The electrical circuits  100  are preferably formed by conventional photolithographic techniques employed in the production of integrated circuits, and included within a planarized layer  105  formed onto substrate  104 . The substrate preferably is then turned over, as indicated by an arrow  106 , and one or more electrical circuits  108  are formed on an opposite surface  110  of substrate  104 , as shown in  FIG. 1B .  
         [0154]     Referring now to  FIG. 1C , preferably, following formation of electrical circuits  100  and  108  on respective surfaces  102  and  110  of substrate  104 , an array of parallel, spaced, elongate optical fiber positioning elements  112  is preferably formed, such as by conventional photolithographic techniques, over a planarized layer  114  including electrical circuits  108  ( FIG. 1B ). As seen in  FIG. 1D , an array of optical fibers  116  is disposed over layer  114 , each fiber being positioned between adjacent positioning elements  112 . The fibers are fixed in place relative to positioning elements  112  and to layer  114  of substrate  104  by means of a suitable adhesive  118 , preferably epoxy, as seen in  FIG. 1E .  
         [0155]     Reference is now made to  FIGS. 2A, 2B ,  2 C, and  2 D, which are simplified sectional illustrations, taken along the lines II-II in  FIG. 1E , of further stages in the production of an electro-optic integrated circuit. As seen in  FIG. 2A , electro-optic components  120 , such as diode lasers, are mounted onto electrical circuit  100  (not shown), included within planarized layer  105 . It is appreciated that electro-optic components  120  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0156]     As shown in  FIG. 2B , a transverse notch  124  is preferably formed, at least partially overlapping the locations of the electro-optic components  120  and extending through the adhesive  118  and partially through each optical fiber  116 . Specifically, in this embodiment, the notch  124  extends through part of the cladding  126  of each fiber  116  and entirely through the core  128  of each fiber. It is appreciated that the surfaces defined by the notch  124  are relatively rough, as shown.  
         [0157]     Turning now to  FIG. 2C , it is seen that a mirror  130  is preferably mounted parallel to one of the rough inclined surfaces  132  defined by notch  124 . Mirror  130  preferably comprises a glass substrate  134 , with a surface  135  facing surface  132  defined by notch  124 , having formed on an opposite surface  136  thereof, a metallic layer or a dichroic filter layer  138 . As seen in  FIG. 2D , preferably, the mirror  130  is securely held in place partially by any suitable adhesive  139 , such as epoxy, and partially by an optical adhesive  140 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index, preferably, is precisely matched to that of the cores  128  of the optical fibers  116 . It is appreciated that optical adhesive  140  may be employed throughout instead of adhesive  139 . The adhesive  140  preferably fills the interstices between the roughened surface  132  defined by notch  124  and surface  135  of mirror  130 .  
         [0158]     Reference is now made to  FIG. 3 , which is an enlarged simplified optical illustration of a portion of  FIG. 2D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  150  of a core  128 , through adhesive  140  and substrate  134  to a reflective surface  152  of layer  138  of mirror  130  and thence through substrate  134 , adhesive  140  and cladding  126 , through layer  114  and substrate  104 , which are substantially transparent to this light. It is noted that the index of refraction of adhesive  140  is close to but not identical to that of cladding  126  and substrate  134 . It is noted that mirror  130  typically reflects light onto electro-optic component  120  ( FIG. 2D ), without focusing or collimating the light.  
         [0159]     Reference is now made to  FIGS. 4A, 4B ,  4 C,  4 D and  4 E, which are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with a preferred embodiment of the present invention. As seen in  FIG. 4A , one or more electrical circuits  200  are preferably formed onto a first surface  202  of a substrate  204 , preferably a substrate that is generally transparent to light within at least part of the wavelength range of 400-1650 nm, typically of thickness between 200-1000 microns. The electrical circuits  200  are preferably formed by conventional photolithographic techniques employed in the production of integrated circuits, and included within a planarized layer  205  formed onto substrate  404 . The substrate preferably is then turned over, as indicated by an arrow  206 , and as shown in  FIG. 4B .  
         [0160]     Referring now to  FIG. 4C , preferably, following formation of electrical circuits  200  on surface  202  of substrate  204 , an array of parallel, spaced, elongate optical fiber positioning elements  212  is preferably formed, such as by conventional photolithographic techniques, over an opposite surface  210  of substrate  204 . As seen in  FIG. 4D , an array of optical fibers  216  is disposed over surface  210  of substrate  204 , each fiber being positioned between adjacent positioning elements  212 . The fibers  216  are fixed in place relative to positioning elements  212  and to surface  210  of substrate  204  by means of a suitable adhesive  218 , preferably epoxy, as seen in  FIG. 4E .  
         [0161]     Reference is now made to  FIGS. 5A, 5B ,  5 C, and  5 D, which are simplified sectional illustrations, taken along the lines V-V in  FIG. 4E , of further stages in the production of an electro-optic integrated circuit. As seen in  FIG. 5A , electro-optic components  220 , such as diode lasers, are mounted onto electrical circuit  200  (not shown), included within planarized layer  205 . It is appreciated that electro-optic components  220  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0162]     As shown in  FIG. 5B , a transverse notch  224  is preferably formed, at least partially overlapping the locations of the electro-optic components  220  and extending through the adhesive  218 , entirely through each optical fiber  216  and partially into substrate  204 . Specifically, in this embodiment, the notch  224  extends through all of cladding  226  of each fiber  216  and entirely through the core  228  of each fiber. It is appreciated that the surfaces defined by the notch  224  are relatively rough, as shown.  
         [0163]     Turning now to  FIG. 5C , it is seen that a partially flat and partially concave mirror  230  is preferably mounted parallel to one of the rough inclined surfaces  32  defined by notch  224 . Mirror  230  preferably comprises a glass substrate  234  having formed thereon a curved portion  236  over which is formed a curved metallic layer or a dichroic filter layer  238 . As seen in  FIG. 5D , preferably, the mirror  230  is securely held in place partially by any suitable adhesive  239 , such as epoxy, and partially by an optical adhesive  240 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  228  of the optical fibers  216 . It is appreciated that optical adhesive  240  may be employed throughout instead of adhesive  239 . Optical adhesive  240  preferably fills the interstices between the roughened surface  232  defined by notch  224  and a surface  242  of mirror  230 .  
         [0164]     Reference is now made to  FIG. 6A , which is an enlarged simplified optical illustration of a portion of  FIG. 5D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  250  of a core  228 , through adhesive  240 , substrate  234  and curved portion  236  to a reflective surface  252  of layer  238  and thence through curved portion  236 , adhesive  240 , substrate  204  and layer  205  which are substantially transparent to this light. It is noted that the index of refraction of adhesive  240  is close to but not identical to that of curved portion  236  and substrates  204  and  234 . In the embodiment of  FIG. 6A , the operation of curved layer  238  is to focus light exiting from end  250  of core  228  onto the electro-optic component  220 .  
         [0165]     Reference is now made to  FIG. 6B , which is an enlarged simplified optical illustration of a portion of  FIG. 5D  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  238  produces collimation rather than focusing of the light exiting from end  250  of core  228  onto the electro-optic component  220 .  
         [0166]     Reference is now made to  FIG. 6C , which is an enlarged simplified optical illustration of a portion of  FIG. 5D  in accordance with yet another embodiment of the present invention wherein a grating  260  is added to curved layer  238 . The additional provision of grating  260  causes separation of light impinging thereon according to its wavelength, such that multispectral light exiting from end  250  of core  228  is focused at multiple locations on electro-optic component  220  in accordance with the wavelengths of components thereof.  
         [0167]     Reference is now made to  FIG. 7 , which is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. The embodiment of  FIG. 7  corresponds generally to that described hereinabove with respect to  FIG. 5D  other than in that a mirror with multiple concave reflective surfaces is provided rather than a mirror with a single such reflective surface. As seen in  FIG. 7 , it is seen that light from optical fiber  316  is directed onto an electro-optic component  320  by a partially flat and partially concave mirror assembly  330 , preferably mounted parallel to one of the rough inclined surfaces  332  defined by notch  324 . Mirror assembly  330  preferably comprises a glass substrate  334  having formed thereon a plurality of curved portions  336  over which are formed a curved metallic layer or a dichroic filter layer  338 . Mirror assembly  330  also defines a reflective surface  340 , which is disposed on a planar surface  342  generally opposite layer  338 . Preferably, the mirror assembly  330  is securely held in place partially by any suitable adhesive  343 , such as epoxy, and partially by an optical adhesive  344 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  328  of the optical fibers  316 . It is appreciated that optical adhesive  344  may be employed throughout instead of adhesive  343 . The optical adhesive  344  preferably fills the interstices between the roughened surface  332  defined by notch  324  and surface  342  of mirror assembly  330 .  
         [0168]     Reference is now made to  FIG. 8A , which is an enlarged simplified optical illustration of a portion of  FIG. 7 . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  350  of a core  328 , through adhesive  344 , substrate  334  and first curved portion  336 , to a curved reflective surface  352  of layer  338  and thence through first curved portion  336  and substrate  334  to reflective surface  340 , from reflective surface  340  through substrate  334  and second curved portion  336  to another curved reflective surface  354  of layer  338  and thence through second curved portion  336 , substrate  334 , adhesive  344 , substrate  304  and layer  305 , which are substantially transparent to this light. It is noted that the index of refraction of adhesive  344  is close to but not identical to that of substrates  304  and  334 . In the embodiment of  FIG. 8A , the operation of curved layer  338  and reflective surface  340  is to focus light exiting from end  350  of core  328  onto the electro-optic component  320 .  
         [0169]     Reference is now made to  FIG. 8B , which is an enlarged simplified optical illustration of a portion of  FIG. 7  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  338  produces collimation rather than focusing of the light exiting from end  350  of core  328  onto the electro-optic component  320 .  
         [0170]     Reference is now made to  FIG. 8C , which is an enlarged simplified optical illustration of a portion of  FIG. 7  in accordance with yet another embodiment of the present invention wherein a reflective grating  360  replaces reflective surface  340 . The additional provision of grating  360  causes separation of light impinging thereon according to its wavelength, such that multispectral light existing from end  350  of core  328  is focused at multiple locations on electro-optic component  320  in accordance with the wavelengths of components thereof.  
         [0171]     Reference is now made to  FIGS. 9A, 9B ,  9 C,  9 D and  9 E, which are simplified pictorial illustrations of initial stages in the production of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. As seen in  FIG. 9A , one or more electrical circuits  400  are preferably formed onto a portion of a surface  402  of a substrate  404 , preferably a glass, silicon or ceramic substrate, typically of thickness between 300-1000 microns. The electrical circuits  400  are preferably formed by conventional photolithographic techniques employed in the production of integrated circuits, and included within a planarized layer  406  formed onto substrate  404 .  
         [0172]     Turning now to  FIG. 9B , it is seen that another portion of the surface  402  is formed with an array of parallel, spaced, elongate optical fiber positioning elements  412  by any suitable technique, such as etching or notching. As seen in  FIG. 9C , an array of optical fibers  416  is engaged with substrate  404 , each fiber being positioned between adjacent positioning elements  412 . The fibers are fixed in place relative to positioning elements  412  and to substrate  404  by means of a suitable adhesive  418 , preferably epoxy, as seen in  FIG. 9D . As seen in  FIG. 9E , a plurality of electro-optic components  420 , such as diode lasers, are mounted in operative engagement with electrical circuits  400 , each electro-optic component  420  preferably being aligned with a corresponding fiber  416 . It is appreciated that electro-optic component  420  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0173]     Reference is now made to  FIGS. 10A, 10B ,  10 C, and  10 D, which are simplified sectional illustrations, taken along the lines X-X in  FIG. 9E , of further stages in the production of an electro-optic integrated circuit. As seen in  FIG. 10A , which corresponds to  FIG. 9E , electro-optic components  420  are each mounted onto an electrical circuit (not shown), included within planarized layer  406  formed onto substrate  404 . As shown in  FIG. 10B , a transverse notch  424  is preferably formed to extend through the adhesive  418  entirely through each optical fiber  416  and partially into substrate  404 . Specifically, in this embodiment, the notch  424  extends through all of cladding  426  of each fiber  416  and entirely through the core  428  of each fiber. It is appreciated that the surfaces defined by the notch  424  are relatively rough, as shown.  
         [0174]     Turning now to  FIG. 10C , it is seen that a partially flat and partially concave mirror assembly  430  is preferably mounted parallel to one of the rough inclined surfaces  432  defined by notch  424 . Mirror assembly  430  preferably comprises a glass substrate  434  having formed thereon a curved portion  436  over which is formed a curved metallic layer or a dichroic filter layer  438 . Mirror assembly  430  also defines a planar surface  440 , generally opposite layer  438 , having formed thereon a metallic layer or a dichroic filter layer  442  underlying part of the curved portion  436 .  
         [0175]     As seen in  FIG. 10D , preferably, the mirror assembly  430  is securely held in place partially by any suitable adhesive  444 , such as epoxy, and partially by an optical adhesive  446 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  428  of the optical fibers  416 . It is appreciated that optical adhesive  446  may be employed throughout instead of adhesive  444 .  
         [0176]     Reference is now made to  FIG. 11A , which is an enlarged simplified optical illustration of a portion of  FIG. 10D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from each electro-optic component  420  through glass substrate  434  and curved portion  436  of mirror assembly  430  into reflective engagement with layer  438  and thence through curved portion  436  and substrate  434  to layer  442  and reflected from layer  442  through substrate  434  and adhesive  446  to focus at an end  450  of a core  428 . In the embodiment of  FIG. 11A , the operation of curved layer  438  is to focus light exiting from electro-optic component  420  onto end  450  of core  428 .  
         [0177]     Reference is now made to  FIG. 11B , which is an enlarged simplified optical illustration of a portion of  FIG. 10D  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  438  produces collimation rather than focusing of the light exiting from electro-optic component  420  onto end  450  of core  428 .  
         [0178]     Reference is now made to  FIG. 11C , which is an enlarged simplified optical illustration of a portion of  FIG. 10D  in accordance with yet another embodiment of the present invention wherein a grating  460  is added to curved layer  438 . The additional provision of grating  460  causes separation of light impinging thereon according to its wavelength, such that only one component of multispectral light exiting electro-optic component  420  is focused on end  450  of core  428 .  
         [0179]     Reference is now made to  FIG. 12 , which is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. The embodiment of  FIG. 12  corresponds generally to that described hereinabove with respect to  FIG. 10D  other than in that a mirror with multiple concave reflective surfaces is provided rather than a mirror with a single such reflective surface. As seen in  FIG. 12 , it is seen that light from an electro-optic component  520 , such as a laser diode, is directed onto a partially flat and partially concave mirror assembly  530 , preferably mounted parallel to one of the rough inclined surfaces  532  defined by notch  524 . It is appreciated that electro-optic component  520  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier. Mirror assembly  530  preferably comprises a glass substrate  534  having formed thereon a plurality of curved portions  536  over which are formed a curved metallic layer or a dichroic filter layer  538 . Mirror assembly  530  also defines a reflective surface  540 , which is disposed on a planar surface  542  generally opposite layer  538 .  
         [0180]     Preferably, the mirror assembly  530  is securely held in place partially by any suitable adhesive  544 , such as epoxy, and partially by an optical adhesive  546 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  528  of the optical fibers  516 . It is appreciated that optical adhesive  546  may be employed throughout instead of adhesive  544 .  
         [0181]     Reference is now made to  FIG. 13A , which is an enlarged simplified optical illustration of a portion of  FIG. 12 . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from each electro-optic component  520  through substrate  534  and a first curved portion  536  of mirror assembly  530  into reflective engagement with a part of layer  538  overlying first curved portion  536  and thence through first curved portion  536  and substrate  534  to reflective surface  540 , where it is reflected back through substrate  534  and a second curved portion  536  to another part of layer  538  overlying second curved portion  536  and is reflected back through second curved portion  536  and substrate  534  to reflective surface  540  and thence through substrate  534  and adhesive  546  to focus at an end  550  of a core  528 . In the embodiment of  FIG. 13A , the operation of curved layer  538  overlying first and second curved portions  536  is to focus light exiting from electro-optic component  520  onto end  550  of core  528 , with enhanced optical properties.  
         [0182]     Reference is now made to  FIG. 13B , which is an enlarged simplified optical illustration of a portion of  FIG. 12  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  538  produces collimation rather than focusing of the light exiting from electro-optic component  520  onto end  550  of core  528 .  
         [0183]     Reference is now made to  FIG. 13C , which is an enlarged simplified optical illustration of a portion of  FIG. 12  in accordance with yet another embodiment of the present invention wherein a reflective grating  560  replaces part of reflective surface  540 . The additional provision of grating  560  causes separation of light impinging thereon according to its wavelength, such that only one component of multispectral light exiting electro-optic component  520  is focused on end  550  of core  528 .  
         [0184]     Reference is now made to  FIGS. 14A, 14B ,  14 C and  14 D, which are simplified pictorial illustrations of further stages in the production of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. As seen in  FIG. 14A , similarly to that shown in  FIG. 5A , electro-optic components  600 , such as edge emitting diode lasers, are mounted onto an electrical circuit (not shown), included within a planarized layer  602  formed onto a surface  603  of a substrate  604 , at the opposite surface  606  of which are mounted optical fibers  616  by means of adhesive  618 . It is appreciated that electro-optic components  600  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0185]     As shown in  FIG. 14B , a transverse notch  624  is preferably formed, extending completely through substrate  604  and entirely through each optical fiber  616  and partially into adhesive  618 . Specifically, in this embodiment, the notch  624  extends through all of cladding  626  of each fiber  616  and entirely through the core  628  of each fiber. It is appreciated that the surfaces defined by the notch  624  are relatively rough, as shown.  
         [0186]     Turning now to  FIG. 14C , it is seen that a partially flat and partially concave mirror assembly  630  is preferably mounted parallel to one of the rough inclined surfaces  632  defined by notch  624 . Mirror assembly  630  preferably comprises a glass substrate  634  having formed thereon a curved portion  636 . A partially planar and partially curved metallic layer or a dichroic filter layer  638  is formed over a surface  640  of substrate  634  and curved portion  636  formed thereon. A reflective layer  642  is formed on an opposite surface  643  of substrate  634  opposite layer  638 .  
         [0187]     As seen in  FIG. 14D , preferably, the mirror assembly  630  is securely held in place partially by any suitable adhesive  644 , such as epoxy, and partially by an optical adhesive  646 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  628  of the optical fibers  616 . It is appreciated that optical adhesive  646  may be employed throughout instead of adhesive  644 .  
         [0188]     Reference is now made to  FIG. 15A , which is a simplified optical illustration of  FIG. 14D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from each electro-optic component  600  through glass substrate  634  and curved portion  636  of mirror assembly  630  into reflective engagement with a curved portion  660  of layer  638  and thence through curved portion  636  and substrate  634  into reflective engagement with layer  642  and thence through multiple reflections through substrate  634  between layer  638  and layer  642 , and then through substrate  634  and adhesive  646  to focus at an end  650  of a core  628 . In the embodiment of  FIG. 15A , the operation of the curved portion of layer  638  is to focus light exiting from electro-optic component  600  onto end  650  of core  628 .  
         [0189]     Reference is now made to  FIG. 15B , which is a simplified optical illustration of  FIG. 14D  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of the curved portion  660  of layer  638  produces collimation rather than focusing of the light exiting from electro-optic component  600  onto end  650  of core  628 .  
         [0190]     Reference is now made to  FIG. 15C , which is a simplified optical illustration of  FIG. 14D  in accordance with yet another embodiment of the present invention wherein a grating  662  is added to the curved portion  660  of layer  638 . The additional provision of grating  662  causes separation of light impinging thereon according to its wavelength, such that only one component of multispectral light exiting electro-optic component  600  is focused on end  650  of core  628 .  
         [0191]     Reference is now made to  FIG. 16 , which is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with still another preferred embodiment of the present invention. The embodiment of  FIG. 16  corresponds generally to that described hereinabove with respect to  FIG. 14D  other than in that a mirror with multiple concave reflective surfaces is provided rather than a mirror with a single such reflective surface. As seen in  FIG. 16 , it is seen that light from an electro-optic component  720 , such as a diode laser, is directed onto a partially flat and partially concave mirror assembly  730 , preferably mounted parallel to one of the rough inclined surfaces  732  defined by notch  724 . It is appreciated that electro-optic component  720  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier. Mirror assembly  730  preferably comprises a glass substrate  734  having formed thereon a plurality of curved portions  736  over which are formed a curved metallic layer or a dichroic filter layer  738 . Mirror assembly  730  also defines a reflective surface  740 , which is disposed on a planar surface  742  generally opposite layer  738 .  
         [0192]     Preferably, the mirror assembly  730  is securely held in place partially by any suitable adhesive  744 , such as epoxy, and partially by an optical adhesive  746 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  728  of the optical fibers  716 . It is appreciated that optical adhesive  746  may be employed throughout instead of adhesive  744 .  
         [0193]     Reference is now made to  FIG. 17A , which is an enlarged simplified optical illustration of a portion of  FIG. 16 . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from each electro-optic component  720  through glass substrate  734  of mirror assembly  730  into reflective engagement with a part of layer  738  overlying the flat portion thereof, and thence through substrate  734  to reflective surface  740 , where it is reflected back through substrate  734  and a first curved portion  736  into reflective engagement with a part of layer  738  overlying first curved portion  736 , and thence through first curved portion  736  and substrate  734  to reflective surface  740 , where it is reflected back through substrate  734  and a second curved portion  736  to another part of layer  738  overlying second curved portion  736  and is reflected back through second curved surface  736  and substrate  734  to reflective surface  740  and thence through substrate  734  and adhesive  746  to focus at an end  750  of a core  728 . In the embodiment of  FIG. 17A , the operation of curved layer  738  overlying first and second curved portions  736  is to focus light exiting from electro-optic component  720  onto end  750  of core  728 , with enhanced optical properties.  
         [0194]     Reference is now made to  FIG. 17B , which is an enlarged simplified optical illustration of a portion of  FIG. 16  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  738  produces collimation rather than focusing of the light exiting from electro-optic component  720  onto end  750  of core  728 .  
         [0195]     Reference is now made to  FIG. 17C , which is an enlarged simplified optical illustration of a portion of  FIG. 16  in accordance with yet another embodiment of the present invention wherein a reflective grating  760  replaces a middle portion of reflective surface  740 . The additional provision of grating  760  causes separation of light impinging thereon according to its wavelength, such that only one component of multispectral light exiting electro-optic component  720  is focused on end  750  of core  728 .  
         [0196]     Reference is now made to  FIGS. 18A, 18B ,  18 C and  18 D, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 4A-6C  in accordance with one embodiment of the present invention. A glass substrate  800 , typically of thickness 200-400 microns, seen in  FIG. 18A , has formed thereon an array of microlenses  802 , typically formed of photoresist, as seen in  FIG. 18B . The microlenses  802  preferably have an index of refraction which is identical or very close to that of substrate  800 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0197]     A thin metal layer  804 , typically aluminum, is formed over the substrate  800  and microlenses  802  as seen in  FIG. 18C , typically by evaporation or sputtering. The substrate  800  and the metal layer  804  formed thereon are then diced by conventional techniques, as shown in  FIG. 18D , thereby defining individual optical elements  806 , each including a curved portion defined by a microlens  802 .  
         [0198]     Reference is now made to  FIGS. 19A, 19B ,  19 C,  19 D and  19 E, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-6C  in accordance with another embodiment of the present invention. A glass substrate  810 , typically of thickness 200-400 microns, seen in  FIG. 19A , has formed thereon an array of microlenses  812 , typically formed of photoresist, as seen in  FIG. 19B . The microlenses  812  preferably have an index of refraction which is identical or very close to that of substrate  810 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0199]     A thin metal layer  814 , typically aluminum, is formed over the substrate  810  and microlenses  812  as seen in  FIG. 19C , typically by evaporation or sputtering. The substrate  810  is then notched from underneath by conventional techniques. As seen in  FIG. 19D , notches  815  are preferably formed at locations partially underlying microlenses  812 .  
         [0200]     Following notching, the substrate  810 , the microlenses  812  and the metal layer  814  formed thereon are diced by conventional techniques, as shown in  FIG. 19E , thereby defining individual optical elements  816 , each including a curved portion defined by part of a microlens  812 .  
         [0201]     Reference is now made to  FIGS. 20A, 20B ,  20 C,  20 D,  20 E and  20 F, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 9A-17C  in accordance with yet another embodiment of the present invention. A glass substrate  820 , typically of thickness 200-400 microns, seen in  FIG. 20A , has formed thereon an array of microlenses  822 , typically formed of photoresist, as seen in  FIG. 20B . The microlenses  822  preferably have an index of refraction which is identical or very close to that of substrate  820 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0202]     A thin metal layer  824 , typically aluminum, is formed over the substrate  820  and microlenses  822 , as seen in  FIG. 20C , typically by evaporation or sputtering. An additional metal layer  825 , typically aluminum, is similarly formed on an opposite surface of substrate  820 . Metal layers  824  and  825  are patterned typically by conventional photolithographic techniques to define respective reflective surfaces  826  and  827  as seen in  FIG. 20D .  
         [0203]     The substrate  820  is notched from underneath by conventional techniques. As seen in  FIG. 20E , notches  828  need not be at locations partially underlying microlenses  822 . Following notching, the substrate  820  is diced by conventional techniques, as shown in  FIG. 20F , at locations intersecting inclined walls of the notches  828 , thereby defining individual optical elements  829 , each including a curved reflective portion defined by a pair of microlenses  822  as well as a flat reflective surface  829 .  
         [0204]     Reference is now made to  FIGS. 21A, 21B ,  21 C,  21 D,  21 E and  21 F which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-17C  in accordance with still another embodiment of the present invention. A glass substrate  830 , typically of thickness 200-400 microns, seen in  FIG. 21A , has formed thereon an array of pairs of microlenses  832 , typically formed of photoresist, as seen in  FIG. 21B . The microlenses  832  preferably have an index of refraction which is identical or very close to that of substrate  830 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0205]     A thin metal layer  834 , typically aluminum, is formed over the substrate  830  and pairs of microlenses  832 , as seen in  FIG. 21C , typically by evaporation or sputtering. An additional metal layer  835 , typically aluminum, is similarly formed on an opposite surface of substrate  830 . Metal layers  834  and  835  are patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  836  and  837  as seen in  FIG. 21D .  
         [0206]     The substrate  830  is notched from underneath by conventional techniques, defining notches  838 , as seen in  FIG. 21E . Following notching, the substrate  830  is diced by conventional techniques, as shown in  FIG. 21F , thereby defining individual optical elements  839 , each including a curved reflective portion defined by a pair of microlenses  823  as well as a flat reflective surface  837 .  
         [0207]     Reference is now made to  FIGS. 22A, 22B ,  22 C,  22 D,  22 E,  22 F and  22 G, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-8C  in accordance with a further embodiment of the present invention. A glass substrate  840 , typically of thickness 200-400 microns, seen in  FIG. 22A , has formed in an underside surface thereof an array of reflective diffraction gratings  841 , as seen in  FIG. 22B , typically by etching. Alternatively, the gratings  841  may be formed on the surface of the substrate  840 , typically by lithography or transfer. An array of pairs of microlenses  842 , typically formed of photoresist, is formed on an opposite surface of substrate  840 , as seen in  FIG. 22C . The microlenses  842  preferably have an index of refraction which is identical or very close to that of substrate  840 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0208]     A thin metal layer  844 , typically aluminum, is formed over the substrate  840  and pairs of microlenses  842  as seen in  FIG. 22D , typically by evaporation or sputtering. Metal layer  844  is preferably patterned, typically by conventional photolithographic techniques, to define a reflective surface  846 , as seen in  FIG. 22E .  
         [0209]     The substrate  840  is notched from underneath by conventional techniques, defining notches  848 , as seen in  FIG. 22F . Following notching, the substrate  840  is diced by conventional techniques, as shown in  FIG. 22G , at locations intersecting inclined walls of the notches  848 , thereby defining individual optical elements  849 , each including a curved reflective portion defined by a pair of microlenses  842  as well as a flat reflective grating  841 .  
         [0210]     Reference is now made to  FIGS. 23A, 23B ,  23 C,  23 D,  23 E,  23 F and  23 G, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 9A-17C  in accordance with yet a further embodiment of the present invention. A glass substrate  850 , typically of thickness 200-400 microns, seen in  FIG. 23A , has formed in an underside surface thereof an array of reflective diffraction gratings  851 , as seen in  FIG. 23B , typically by etching. Alternatively, the gratings  851  may be formed on the surface of the substrate  850 , typically by lithography or transfer. An array of pairs of microlenses  852 , typically formed of photoresist, is formed on an opposite surface of substrate  850 , as seen in  FIG. 23C . The microlenses  852  preferably have an index of refraction which is identical or very close to that of substrate  850 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0211]     A thin metal layer  854 , typically aluminum, is formed over the substrate  850  and pairs of microlenses  852  as seen in  FIG. 23D , typically by evaporation or sputtering. An additional metal layer  855  is similarly formed on an opposite surface of the substrate  850 . Metal layers  854  and  855  are preferably patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  856  and  857 , as seen in  FIG. 23E .  
         [0212]     The substrate  850  is notched from underneath by conventional techniques, defining notches  858 , as seen in  FIG. 23F . Following notching, the substrate  850  is diced by conventional techniques, as shown in  FIG. 23G , at locations intersecting inclined walls of the notches  858 , thereby defining individual optical elements  859 , each including a curved reflective portion defined by a pair of microlenses  852  as well as a flat reflective grating  851  and flat reflective surfaces  857 .  
         [0213]     Reference is now made to  FIGS. 24A, 24B ,  24 C,  24 D,  24 E,  24 F and  24 G, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 1A-17C  in accordance with a still further embodiment of the present invention. A glass substrate  860 , typically of thickness 200-400 microns, seen in  FIG. 24A , has formed therein an array of reflective diffraction gratings  861 , as seen in  FIG. 24B , typically by etching. Alternatively, the gratings  861  may be formed on the surface of the substrate  860 , typically by lithography or transfer. An array of microlenses  862 , typically formed of photoresist, is formed on the same surface of substrate  860 , as seen in  FIG. 24C . The microlenses  862  preferably have an index of refraction which is identical or very close to that of substrate  860 . This may be achieved by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, and jet printing.  
         [0214]     A thin metal layer  864 , typically aluminum, is formed over the substrate  860  and microlenses  862  as seen in  FIG. 24D , typically by evaporation or sputtering. An additional metal layer  865  is similarly formed on an opposite surface of the substrate  860 . Metal layers  864  and  865  are preferably patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  866  and  867 , as seen in  FIG. 24E .  
         [0215]     The substrate  860  is notched from underneath by conventional techniques, defining notches  868 , as seen in  FIG. 24F . Following notching, the substrate  860  is diced by conventional techniques, as shown in  FIG. 24G , at locations intersecting inclined walls of the notches  868 , thereby defining individual optical elements  869 , each including a curved reflective surface  866  defined by a microlens  862  as well as a flat reflective grating  861  and a flat reflective surface  867 .  
         [0216]     Reference is now made to  FIGS. 25A, 25B ,  25 C and  25 D, which are simplified illustrations of multiple stages in the production of a multi-chip module in accordance with a preferred embodiment of the present invention. As seen in  FIG. 25A , a substrate  900 , typically formed of silicon and having a thickness of 300-800 microns, has formed thereon at least one dielectric passivation layer  902 , at least one metal layer  904  and at least one overlying dielectric layer  906 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands. Vias  908 , connected to at least one metal layer  904 , extend through layer  902  to the substrate  900 .  
         [0217]     As seen in  FIG. 25B , an array of openings  910  is formed by removing portions of substrate  900  at a location underlying vias  908 . Preferably, the entire thickness of the substrate  900  is removed. The removal of substrate  900  may be achieved by using conventional etching techniques and, preferably, provides a volume of dimensions of at least 600 microns in width.  
         [0218]     As seen in  FIG. 25C , metallic bumps  912 , preferably solder bumps, are preferably formed onto the thus exposed surfaces of vias  908 . As seen in  FIG. 25D , integrated circuit chips  914  are preferably located in openings  910  and operatively engaged with vias  908  by being soldered to bumps  912 , thus creating a multi-chip module, wherein integrated circuit chips  914  reside within the substrate of the module.  
         [0219]     Reference is now made  FIG. 26 , which is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including a laser light source  920  formed on an integrated circuit chip  922 , located in an opening  924  formed in a module substrate  926 .  
         [0220]     Reference is now made to  FIG. 27 , which is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including an optical detector  930  formed on an integrated circuit chip  932 , located in an opening  934  formed in a module substrate  936 .  
         [0221]     Reference is now made to  FIG. 28 , which is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including an electrical element  940  formed on an integrated circuit chip  942  located in an opening  944  formed in a module substrate  946 .  
         [0222]     Reference is now made to  FIG. 29 , which is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including multiple elements  950  located in multiple recesses  952  formed within a substrate  954 . These elements may by any suitable electrical or electro-optic element.  
         [0223]     Reference is now made to  FIG. 30 , which is a simplified illustration of a multi-chip module of the type referenced in  FIGS. 25A-25D , including multiple stacked elements located in recesses formed within substrates. As seen in  FIG. 30 , a substrate  1000 , typically formed of silicon and having a thickness of 500-1000 microns, has formed thereon at least one dielectric passivation layer  1002 , at least one metal layer  1004  and at least one overlying dielectric layer  1006 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands. Vias  1008 , connected to at least one metal layer  1004  extend through layer  1002  to the substrate  1000 . At least one opening  1010  is formed by removing a portion of substrate  1000  at a location underlying vias  1008 . Preferably, the entire thickness of substrate  1000  is removed. The removal of substrate  1000  may be achieved by using conventional etching techniques and provides a volume of dimensions of at least 1000 microns in width. Metallic bumps  1012 , preferably solder bumps, are preferably formed onto the thus exposed surfaces of vias  1008 .  
         [0224]     Disposed within opening  1010  is a substrate  1020 , typically formed of silicon and having a thickness of 300-800 microns, having formed thereon at least one dielectric passivation layer  1022 , at least one metal layer  1024  and at least one overlying dielectric layer  1026 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands. Vias  1028 , connected to at least one metal layer  1024 , extend through layer  1022  to the substrate  1020 . At least one opening  1030  is formed by removing portions of substrate  1020  at a location underlying vias  1028 . Preferably, the entire thickness of substrate  1020  is removed. The removal of substrate  1020  may be achieved by using conventional etching techniques and provides a volume of dimensions of at least 600 microns in width. Metallic bumps  1032 , preferably solder bumps, are preferably formed onto the thus exposed surfaces of vias  1028 . Additional metallic bumps  1034 , preferably solder bumps, are preferably formed onto ends of vias  1036  which are preferably connected to at least one metal layer  1024 , which need not necessarily be connected to bumps  1032 . Bumps  1012  and  1034  are preferably soldered together to mount substrate  1020  within substrate  1000 .  
         [0225]     An integrated circuit chip  1040  is preferably located in opening  1030  and operatively engaged with vias  1028  by being soldered to bumps  1032 , thus creating a multi-chip module, wherein at least one integrated circuit chip  1040  resides within substrate  1020 , which in turn resides within substrate  1000 .  
         [0226]     It is appreciated that any suitable number of substrates, such as substrates  1000  and  1020 , may be nested within each other, as shown in  FIG. 30 , and that each such substrate may have multiple openings formed therein.  
         [0227]     Reference is now made to  FIGS. 31A, 31B ,  31 C and  31 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with a preferred embodiment of the present invention. In the embodiment of  FIG. 31A , similarly to  FIG. 2A  described hereinabove, electro-optic components  1120 , such as diode lasers, are mounted onto an electrical circuit (not shown), included within a planarized layer  1122  formed onto a substrate  1123 . It is appreciated that electro-optic components  1120  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0228]     As shown in  FIG. 31B , a transverse notch  1124  is preferably formed, at least partially overlapping the locations of the electro-optic components  1120  and extending through an adhesive  1125  and partially through each of a plurality of optical fibers  1126 . Specifically, in this embodiment, the notch  1124  extends entirely through the cladding  1127  of each fiber  1126  and entirely through the core  1128  of each fiber. It is appreciated that the surfaces defined by the notch  1124  are relatively rough, as shown.  
         [0229]     Turning now to  FIG. 31C , it is seen that a mirror  1130 , typically of the type illustrated in  FIGS. 2C and 3 , is preferably mounted parallel to one of the rough inclined surfaces  1132  defined by notch  1124 . Mirror  1130  preferably comprises a glass substrate  1134  having formed on a surface  1136  thereof, a metallic layer or a dichroic filter layer  1138 . A partially flat and partially concave mirror  1139 , typically similar to the type illustrated in  FIGS. 5C and 6A , is preferably mounted parallel to an opposite one of the rough inclined surfaces, here designated  1140 . Mirror  1139  preferably comprises a glass substrate  1142  having formed thereon a curved portion  1144  over which is formed a curved metallic layer or a dichroic filter layer  1146 .  
         [0230]     As seen in  FIG. 31D , the mirrors  1130  and  1139  are securely held in place by any suitable adhesive  1148 , such as epoxy, and partially by an optical adhesive  1150 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  1128  of the optical fibers  1126 . The adhesive  1150  preferably fills the interstices between the roughened surfaces  1132  and  1140  defined by notch  1124  and respective mirrors  1130  and  1139 . It is appreciated that optical adhesive  1150  may be employed throughout instead of adhesive  1148 . It is noted that the index of refraction of adhesive  1150  is close to but not identical to that of substrates  1123 ,  1134  and  1142 .  
         [0231]     Reference is now made to  FIG. 32 , which is an enlarged simplified optical illustration of a portion of  FIG. 31D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1151  of a core  1128 , through adhesive  1150  and glass substrate  1134  to a reflective surface  1152  of mirror  1130  and thence through glass substrate  1134 , adhesive  1150 , substrate  1123  and layer  1122 , which are substantially transparent to this light. Similarly, a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1161  of core  1128 , through adhesive  1150 , glass substrate  1142  and curved portion  1144  to a reflective surface  1162  of mirror  1139  and thence through curved portion  1144 , glass substrate  1142 , adhesive  1150 , substrate  1123  and layer  1122 , which are substantially transparent to this light.  
         [0232]     It is noted that mirror  1130  typically reflects light onto an electro-optic component  1120 , here designated  1170 , without focusing or collimating the light, while mirror  1139  focuses light reflected thereby onto another electro-optic component  1120 , here designated  1172 . It is appreciated that any suitable combination of mirrors having any suitable optical properties, such as collimating and focusing, may alternatively be employed.  
         [0233]     Reference is now made to  FIGS. 33A, 33B ,  33 C and  33 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with another preferred embodiment of the present invention. In the embodiment of  FIG. 33A , similarly to  FIG. 31A  described hereinabove, electro-optic components  1220 , such as diode lasers, are mounted onto an electrical circuit (not shown), included within a planarized layer  1222  formed onto a substrate  1223 . It is appreciated that electro-optic components  1220  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier. In contrast to the embodiment of  FIG. 31A , here the electro-optic components  1220  are located in openings or recesses formed within the substrate  1223 , similarly to the structure shown in  FIG. 29 .  
         [0234]     As shown in  FIG. 33B , a transverse notch  1224  is preferably formed, at least partially overlapping the locations of at least one of the electro-optic components  1220  and extending through an adhesive  1225  and partially through each of a plurality of optical fibers  1226 . Specifically, in this embodiment, the notch  1224  extends through part of the cladding  1227  of each fiber  1226  and entirely through the core  1228  of each fiber. It is appreciated that the surfaces defined by the notch  1224  are relatively rough, as shown.  
         [0235]     Turning now to  FIG. 33C , it is seen that a mirror  1230 , typically, similar to the type illustrated in  FIGS. 2C and 3 , is preferably mounted parallel to one of the rough inclined surfaces, here designated  1232 , defined by notch  1224 . Mirror  1230  preferably comprises a glass substrate  1234  having formed on a surface  1236  thereof, a metallic layer or a dichroic filter layer  1238 . A partially flat and partially concave mirror  1239 , typically similar to the type illustrated in  FIGS. 5C and 6A , is preferably mounted parallel to an opposite one of the rough inclined surfaces, here designated  1240 . Mirror  1239  preferably comprises a glass substrate  1242  having formed thereon a curved portion  1244  over which is formed a curved metallic layer or a dichroic filter layer  1246 .  
         [0236]     As seen in  FIG. 33D , the mirrors  1230  and  1239  are securely held in place partially by any suitable adhesive  1248 , such as epoxy, and partially by an optical adhesive  1250 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  1228  of the optical fibers  1226 . The adhesive  1250  preferably fills the interstices between the roughened surfaces  1232  and  1240  defined by notch  1224  and respective mirrors  1230  and  1239 . It is appreciated that optical adhesive  1250  may be employed throughout instead of adhesive  1248 . It is noted that the index of refraction of adhesive  1250  is close to but not identical to that of cladding  1227 , substrate  1242  and curved portion  1244 .  
         [0237]     Reference is now made to  FIG. 34 , which is an enlarged simplified optical illustration of a portion of  FIG. 33D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1251  of a core  1228 , through adhesive  1250  to a reflective surface  1252  of mirror  1230  and thence through adhesive  1250  and cladding  1227 , and then through layer  1222 , which is substantially transparent to this light. Similarly, a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1261  of core  1228 , through adhesive  1250 , substrate  1242  and curved portion  1244 , to a reflective surface  1262  of mirror  1239  and thence through curved portion  1244 , adhesive  1250  and cladding  1227 , and then through layer  1222 , which is substantially transparent to this light.  
         [0238]     It is noted that mirror  1230  typically reflects light onto an electro-optic component  1220 , here designated  1270 , without focusing or collimating the light, while mirror  1239  focuses light reflected thereby onto another electro-optic component  1220 , here designated  1272 . It is appreciated that any suitable combination of mirrors having any suitable optical properties, such as collimating and focusing, may alternatively be employed.  
         [0239]     Reference is now made to  FIGS. 35A, 35B ,  35 C and  35 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with a preferred embodiment of the present invention. In the embodiment of  FIG. 35A , similarly to  FIG. 31A  described hereinabove, electro-optic components  1320 , such as diode lasers, are mounted onto an electrical circuit (not shown), included within a planarized layer  1322  formed onto a substrate  1323 . It is appreciated that electro-optic components  1320  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier. As distinct from the embodiment of  FIGS. 31A-32 , here at least first and second separate fibers  1325  and  1326  are fixed to substrate  1323 , preferably by an adhesive  1327 . The fibers  1325  and  1326  may be identical, similar or different, and need not be arranged in a mutually aligned spatial relationship.  
         [0240]     As shown in  FIG. 35B , a transverse notch  1328  is preferably formed, at least partially overlapping the locations of the electro-optic components  1320  and extending through adhesive  1327  and partially through at least each of optical fibers  1325  and  1326 . Specifically, in this embodiment, the notch  1328  extends entirely through of the cladding  1330  and  1331  and entirely through the cores  1332  and  1333  of fibers  1325  and  1326  respectively. It is appreciated that the surfaces defined by the notch  1328  are relatively rough, as shown.  
         [0241]     Turning now to  FIG. 35C , it is seen that a mirror  1334 , typically of the type illustrated in  FIGS. 2C and 3 , is preferably mounted parallel to one of the rough inclined surfaces  1335  defined by notch  1328 . Mirror  1334  preferably comprises a glass substrate  1336  having formed on a surface  1337  thereof, a metallic layer or a dichroic filter layer  1338 . A partially flat and partially concave mirror  1339 , typically similar to the type illustrated in  FIGS. 5C and 6A , is preferably mounted parallel to an opposite one of the rough inclined surfaces, here designated  1340 . Mirror  1339  preferably comprises a glass substrate  1342  having formed thereon a curved portion  1344  over which is formed a curved metallic layer or a dichroic filter layer  1346 .  
         [0242]     As seen in  FIG. 35D , the mirrors  1334  and  1339  are securely held in place partially by any suitable adhesive  1348 , such as epoxy, and partially by optical adhesive  1350 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive indices preferably are precisely matched to those of the cores  1332  and  1333  of the optical fibers  1325  and  1326  respectively. The adhesive  1350  preferably fills the interstices between the roughened surfaces  1335  and  1340  defined by notch  1328  and respective mirrors  1334  and  1339 . It is appreciated that optical adhesive  1350  may also be employed instead of adhesive  1348 . It is noted that the index of refraction of adhesive  1350  is close to but not identical to that of substrates  1323 ,  1336  and  1342 .  
         [0243]     Reference is now made to  FIG. 36 , which is an enlarged simplified optical illustration of a portion of  FIG. 35D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1352  of a core  1332  of a fiber  1325 , through adhesive  1350  and substrate  1336  to a reflective surface  1354  of mirror  1334  and thence through substrate  1336 , adhesive  1350 , substrate  1323  and layer  1322 , which are substantially transparent to this light. Similarly, a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1362  of core  1333  of fiber  1326 , through adhesive  1350 , substrate  1342  and curved portion  1344  to a reflective surface  1364  of mirror  1339  and thence through curved portion  1344 , substrate  1342 , adhesive  1350 , substrate  1323  and layer  1322 , which are substantially transparent to this light.  
         [0244]     It is noted that mirror  1334  typically reflects light onto an electro-optic component  1320 , here designated  1370 , without focusing or collimating the light, while mirror  1339  focuses light reflected thereby onto another electro-optic component  1320 , here designated  1372 . It is appreciated that any suitable combination of mirrors having any suitable optical properties, such as collimating and focusing, may alternatively be employed.  
         [0245]     Reference is now made to  FIGS. 37A, 37B ,  37 C and  37 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated assembly in accordance with another preferred embodiment of the present invention. The embodiment of  FIGS. 37A-37D  is similar to the embodiments of  FIGS. 33A-33D  and  35 A- 35 D, described hereinabove. As shown in  FIG. 37A , electro-optic components  1400 , such as diode lasers, are mounted onto an electrical circuit (not shown), included within a planarized layer  1402  formed onto a substrate  1404 . It is appreciated that electro-optic components  1400  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating and a semiconductor optical amplifier. In contrast to the embodiment of  FIG. 35A , here the electro-optic components  1400  are located in openings or recesses formed within the substrate  1404 , similarly to the structure shown in  FIG. 33A . As distinct from the embodiment of  FIG. 33A , here at least first and second separate fibers  1406  and  1408  are fixed to substrate  1404 , preferably by an adhesive  1410 , similarly to the structure shown in  FIG. 35A . The fibers  1406  and  1408  may be identical, similar or different and need not be arranged in a mutually aligned spatial relationship.  
         [0246]     As shown in  FIG. 37B , a transverse notch  1412  is preferably formed, at least partially overlapping the locations of at least one of the electro-optic components  1400  and extending through an adhesive  1410  and partially through each of a plurality of optical fibers  1406  and  1408 . Specifically, in this embodiment, the notch  1412  extends through part of the claddings  1414  and  1416  and entirely through the cores  1418  and  1420  of fibers  1406  and  1408 , respectively. It is appreciated that the surfaces defined by the notch  1412  are relatively rough, as shown.  
         [0247]     Turning now to  FIG. 37C , it is seen that a mirror  1430 , typically, similar to the type illustrated in  FIGS. 2C and 3 , is preferably mounted parallel to one of the rough inclined surfaces, here designated  1432 , defined by notch  1412 . Mirror  1430  preferably comprises a glass substrate  1434  having formed on a surface  1436  thereof, a metallic layer or a dichroic filter layer  1438 . A partially flat and partially concave mirror  1439 , typically similar to the type illustrated in  FIGS. 5C and 6A , is preferably mounted parallel to an opposite one of the rough inclined surfaces, here designated  1440 . Mirror  1439  preferably comprises a glass substrate  1442  having formed thereon a curved portion  1444  over which is formed a curved metallic layer or a dichroic filter layer  1446 .  
         [0248]     As seen in  FIG. 37D , the mirrors  1430  and  1439  are securely held in place partially by any suitable adhesive  1448 , such as epoxy, and partially by an optical adhesive  1450 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  1418  and  1420  of the optical fibers  1406  and  1408 , respectively. The adhesive  1450  preferably fills the interstices between the roughened surfaces  1432  and  1440  defined by notch  1412  and respective mirrors  1430  and  1439 . It is appreciated that optical adhesive  1450  may be employed throughout instead of adhesive  1448 . It is noted that the index of refraction of adhesive  1450  is close to but not identical to that of the curved portion  1444 , substrate  1442  and claddings  1414  and  1416  of the optical fibers  1406  and  1408 , respectively.  
         [0249]     Reference is now made to  FIG. 38 , which is an enlarged simplified optical illustration of a portion of  FIG. 37D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 mm, from an end  1451  of a core  1418 , through adhesive  1450  to a reflective surface  1452  of mirror  1430  and thence through adhesive  1450  and cladding  1414 , through layer  1402 , which is substantially transparent to this light. Similarly, a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 600-1650 nm, from an end  1462  of core  1420 , through adhesive  1450 , substrate  1442  and curved portion  1444  to a reflective surface  1464  of mirror  1439  and thence through curved portion  1444 , adhesive  1450  and cladding  1416 , through layer  1402 , which is substantially transparent to this light.  
         [0250]     It is noted that mirror  1430  typically reflects light onto an electro-optic component  1400 , here designated  1470 , without focusing or collimating the light, while mirror  1439  focuses light reflected thereby onto another electro-optic component  1400 , here designated  1472 . It is appreciated that any suitable combination of mirrors having any suitable optical properties, such as collimating and focusing, may alternatively be employed.  
         [0251]     Reference is now made to  FIGS. 39A, 39B ,  39 C, and  39 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated circuit in accordance with another preferred embodiment of the present invention. As seen in  FIG. 39A , electro-optic components  1520 , such as a diode laser, are each mounted onto an electrical circuit (not shown), included within a planarized layer  1522  formed onto substrate  1524 . It is appreciated that electro-optic components  1520  may be any suitable electro-optic component, such as a laser diode, diode detector, waveguide, array waveguide grating or a semiconductor optical amplifier.  
         [0252]     As shown in  FIG. 39B , a transverse cut  1526  is preferably formed to extend partially through the substrate  1524 . It is appreciated that a surface  1528  defined by the cut  1526  is relatively rough, as shown.  
         [0253]     Turning now to  FIG. 39C , it is seen that a partially flat and partially concave mirror assembly  1530  is preferably mounted parallel to the rough inclined surface  1528  defined by the cut  1526 . Mirror assembly  1530  preferably comprises a glass substrate  1534  having formed thereon a curved portion  1536  over which is formed a curved metallic layer or a dichroic filter layer  1538 . Mirror assembly  1530  also defines a flat surface  1540 , having formed thereon a metallic layer or a dichroic filter layer  1542  partially underlying the curved portion  1536 . As seen in  FIG. 39D , preferably, the mirror assembly  1530  is securely held in place by any suitable adhesive  1544 , such as epoxy.  
         [0254]     Reference is now made to  FIG. 40 , which is a simplified optical illustration corresponding to  FIG. 39D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-165 nm, from each electro-optic component  1520  through glass substrate  1534  and curved portion  1536  of mirror assembly  1530  into reflective engagement with layer  1538  and thence through curved portion  1536  and substrate  1534  to layer  1542  and reflected from layer  1542  through substrate  1534  as a parallel beam.  
         [0255]     It is appreciated that the electro-optic integrated circuit described in reference to  FIGS. 39A-40  may be configured to operate as either a light transmitter or a light receiver, as described hereinbelow with reference to  FIGS. 43-45 .  
         [0256]     Reference is now made to  FIGS. 41A, 41B ,  41 C, and  41 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated circuit in accordance with another preferred embodiment of the present invention. As seen in  FIG. 41A , an optical fiber  1620  is mounted onto a substrate  1622 , preferably by means of adhesive  1623 . As shown in  FIG. 41B , a transverse cut  1624  is preferably formed to extend through the adhesive  1623 , the optical fiber  1620  and the substrate  1622 . Specifically, in this embodiment, the cut  1624  extends through the cladding  1626  of fiber  1620  and entirely through the core  1628  of the fiber. It is appreciated that a surface  1629  defined by the cut  1624  is relatively rough, as shown.  
         [0257]     Turning now to  FIG. 41C , it is seen that a partially flat and partially concave mirror assembly  1630  is preferably mounted parallel to the rough inclined surface  1629  defined by the cut  1624 . Mirror assembly  1630  preferably comprises a glass substrate  1634  having formed thereon a curved portion  1636  over which is formed a curved metallic layer or a dichroic filter layer  1638 . Mirror assembly  1630  also defines a flat surface  1640  having formed thereon a metallic layer or a dichroic filter layer  1642 , partially underlying the curved portion  1636 . As seen in  FIG. 41D , preferably, the mirror assembly  1630  is securely held in place by an optical adhesive  1644 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  1628  of the optical fibers  1620 .  
         [0258]     Reference is now made to  FIG. 42 , which is a simplified optical illustration corresponding to  FIG. 41D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  1646  of core  1628  of fiber  1620  through adhesive  1644  and substrate  1634  and curved portion  1636  of mirror assembly  1630  into reflective engagement with layer  1638  and thence through curved portion  1636  and substrate  1634  to layer  1642  and reflected from layer  1642  through substrate  1634  as a parallel beam.  
         [0259]     It is appreciated that the electro-optic integrated circuit described in reference to  FIGS. 41A-42  may be configured to operate as either a light transmitter or a light receiver, as described hereinbelow with reference to  FIGS. 43-45 .  
         [0260]     Reference is now made to  FIG. 43 , which illustrates optical coupling through free space between the electro-optic integrated circuit of  FIG. 40 , here designated by reference numeral  1700  and the electro-optic integrated circuit of  FIG. 42 , here designated by reference numeral  1702 . It is appreciated that either of electro-optic integrated circuits  1700  and  1702  may transmit light to the other, which receives the light, along a parallel beam.  
         [0261]     Reference is now made to  FIG. 44 , which illustrates optical coupling through free space between an electro-optic integrated circuit of  FIG. 40 , here designated by reference numeral  1704  and another electro-optic integrated circuit of  FIG. 40 , here designated by reference numeral  1706 . It is appreciated that either of electro-optic integrated circuits  1704  and  1706  may transmit light to the other, which receives the light, along a parallel beam.  
         [0262]     Reference is now made to  FIG. 45 , which illustrates optical coupling through free space between an electro-optic integrated circuit of  FIG. 42 , here designated by reference numeral  1708  and another electro-optic integrated circuit of  FIG. 42 , here designated by reference numeral  1710 . It is appreciated that either of electro-optic integrated circuits  1708  and  1710  may transmit light to the other, which receives the light, along a parallel beam.  
         [0263]     Reference is now made to  FIGS. 46A, 46B ,  46 C, and  46 D, which are simplified sectional illustrations of stages in the production of an electro-optic integrated circuit in accordance with another preferred embodiment of the present invention. As seen in  FIG. 46A , an optical fiber  1800  is fixed in place on substrate  1802  by means of a suitable adhesive  1804 , preferably epoxy. As shown in  FIG. 46B , a transverse notch  1824  is preferably formed, extending through the adhesive  1804  entirely through the optical fiber  1800  and partially into substrate  1802 . Specifically, in this embodiment, the notch  1824  extends through all of cladding  1826  of the fiber  1800  and entirely through the core  1828  of the fiber. It is appreciated that the surfaces defined by the notch  1824  are relatively rough, as shown.  
         [0264]     Turning now to  FIG. 46C , it is seen that a partially flat and partially concave mirror  1830  is preferably mounted parallel to one of the rough inclined surfaces  1832  defined by notch  1824 . Mirror  1830  preferably comprises a glass substrate  1834  having formed thereon a curved portion  1836  over which is formed a curved metallic layer or a dichroic filter layer  1838 . As seen in  FIG. 46D , preferably, the mirror  1830  is securely held in place partially by any suitable adhesive  1844 , such as epoxy, and partially by an optical adhesive  1846 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  1828  of the optical fibers  1800 . It is appreciated that optical adhesive  1846  may be employed throughout instead of adhesive  1844 . The optical adhesive  1846  preferably fills the interstices between the roughened surface  1832  defined by notch  1824  and a surface  1848  of mirror  1830 .  
         [0265]     Reference is now made to  FIG. 47 , which is an enlarged simplified optical illustration of a portion of  FIG. 46D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  1850  of a core  1828 , through adhesive  1846 , substrate  1834  and curved portion  1836 , to a reflective surface  1852  of layer  1838  and thence through curved portion  1836 , adhesive  1846  and substrate  1802 , which are substantially transparent to this light. It is noted that the index of refraction of adhesive  1846  is close to but not identical to that of curved portion  1836  and substrates  1802  and  1834 . As seen in  FIG. 47 , the operation of curved layer  1838  is to collimate light exiting from end  1850  of core  1828  through substrate  1802  as a parallel beam.  
         [0266]     Reference is now made to  FIG. 48 , which illustrates optical coupling through free space between an electro-optic integrated circuit of  FIG. 46D , here designated by reference numeral  1900 , and another electro-optic integrated circuit of  FIG. 46D , here designated by reference numeral  1902 . It is appreciated that either of electro-optic integrated circuits  1900  and  1902  may transmit light to the other, which receives the light, along a parallel beam.  
         [0267]     Reference is now made to  FIG. 49 , which illustrates optical coupling through free space between an electro-optic integrated circuit of  FIG. 46D , here designated by reference numeral  1904 , and an optical device  1906 . Optical device  1906  may be any optical device that receives or transmits light along a parallel beam. It is appreciated that either of electro-optic integrated circuit  1904  and optical device  1906  may transmit light to the other, which receives the light, along a parallel beam.  
         [0268]     Reference is now made to  FIGS. 50A, 50B ,  50 C,  50 D and  50 E, which are simplified pictorial illustrations of stages in the production of an electro-optic integrated circuit constructed and operative in accordance with still another preferred embodiment of the present invention. As seen in  FIG. 50A , a substrate  2000 , typically formed of silicon and having a thickness of 300-800 microns, has formed thereon at least one dielectric passivation layer  2002 , at least one metal layer  2004  and at least one overlying dielectric layer  2006 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands. Vias, (not shown) connected to at least one metal layer  2004 , extend through layer  2002  to the substrate  2000 . One or more semiconductor functional blocks  2008  are preferably formed on substrate  2000 .  
         [0269]     As seen in  FIG. 50B , one or more openings  2010  are formed by removing portions of the substrate  2000  from the underside thereof, as shown for example in  FIG. 25B . The removal of portions of substrate  2000  may be achieved by using conventional etching techniques and, preferably, provides a volume of dimensions of at least 600 microns in width.  
         [0270]     As seen in  FIG. 50C , integrated circuit chips  2014  are preferably located in openings  2010 . These chips may be operatively engaged with vias (not shown) by being soldered to bumps (not shown) as illustrated for example in  FIG. 25D , thus creating an optoelectronic integrated circuit, wherein integrated circuit chips  2014  reside within the substrate of the integrated circuit.  
         [0271]     As seen in  FIG. 50D , one or more fibers  2016  are fixed to substrate  2000 , preferably by an adhesive (not shown), similarly to that shown in  FIG. 37A . Multiple fibers  2016  may be identical, similar or different and need not be arranged in a mutually aligned spatial relationship.  
         [0272]     As shown in  FIG. 50E , it is seen that a mirror  2030 , typically of the type illustrated in any of  FIGS. 18A-24G , is preferably mounted in operative engagement with each fiber  2016 .  
         [0273]     Reference is now made to  FIG. 51 , which is a simplified functional illustration of a preferred embodiment of the structure of  FIG. 50E . As seen in  FIG. 51 , a high frequency optical signal  2100 , typically of frequency 10 GHz, passes through a fiber  2102  and is reflected by a mirror  2104  onto a diode  2106 , which may be located in a recess  2107 . An output electrical signal  2108  from diode  2106  is supplied to an amplifier  2110 , which may be located in a recess  2111  and need not be formed of silicon, but could be formed, for example, of gallium arsenide or indium phosphide. The amplified output  2112  of amplifier  2110  may be provided to a serializer/deserializer  2114 , which may be located in a recess  2115  and need not be formed of silicon, but could be formed, for example, of gallium arsenide or indium phosphide.  
         [0274]     An output signal  2116  from serializer/deserializer  2114  is preferably fed to one or more semiconductor functional blocks  2118  for further processing. A laser  2120 , which may be located in a recess  2122 , may employ an electrical output from a functional block  2118  to produce a modulated light beam  2124 , which is reflected by a mirror  2126  so as to pass through a fiber  2128 . It is appreciated that electro-optic integrated circuit devices  2106  and  2120  may be configured to operate as either a light transmitter or a light receiver or both.  
         [0275]     It is appreciated that in addition to the substrate materials described hereinabove the substrates may comprise glass, silicon, sapphire, alumina, aluminum nitride, boron nitride or any other suitable material.  
         [0276]     Reference is now made to  FIGS. 52A and 52B , which are simplified pictorial illustrations of a packaged electro-optic circuit  3100 , having integrally formed therein an optical connector and electrical connections, alone and in conjunction with a conventional optical connector.  
         [0277]     As seen in  FIGS. 52A and 52B , a packaged electro-optic circuit  3100  is provided in accordance with a preferred embodiment of the present invention and includes an at least partially transparent substrate  3102 , typically glass. Electrical circuitry (not shown) is formed, as by conventional photolithographic techniques, over one surface of substrate  3102  and is encapsulated by a layer  3104  of a protective material such as BCB, commercially available from Dow Corning of the U.S.A. An array  3106  of electrical connections, preferably in the form of conventional solder bumps, communicates with the electrical circuitry via conductive pathways (not shown) extending through the protective material of layer  3104 .  
         [0278]     Formed on a surface of substrate  3102  opposite to that adjacent layer  3104  there are defined optical pathways (not shown) which communicate with an array of optical fibers  3108 , whose ends are aligned along an edge  3110  of the substrate  3102 . Preferably, physical alignment bores  3112  are aligned with the array of optical fibers  3108 . The bores  3112  are preferably defined by cylindrical elements, which, together with the optical fibers  3108  and the optical pathways, are encapsulated by a layer  3114  of protective material, preferably epoxy.  
         [0279]      FIG. 52B  shows a conventional MPO type optical connector  3116 , such as an MPO connector manufactured by SENKO Advanced Components, Inc. of Marlborough, Mass., USA., arranged for mating contact with the packaged electro-optic circuit  3100 , wherein alignment pins  3118  of connector  3116  are arranged to seat in alignment bores  3112  of the electro-optic circuit  3100  and optical fiber ends (not shown) of connector  3116  are arranged in butting aligned relationship with the ends of the array  3108  of optical fibers in packaged electro-optic circuit  3100 .  
         [0280]     Reference is now made to  FIGS. 53A, 53B ,  53 C,  53 D,  53 E and  53 F, which are simplified pictorial and sectional illustrations of a first plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B . Turning to  FIG. 53A , it is seen that electrical circuits  3120  are preferably formed onto a first surface  3122  of substrate  3102 , at least part of which is transparent to light within at least part of the wavelength range of 600-1650 nm. Substrate  3102  is preferably of thickness between 200-800 microns. The electrical circuits  3120  are preferably formed by conventional photolithographic techniques employed in the production of integrated circuits.  
         [0281]     The substrate shown in  FIG. 53A  is turned over, as indicated by an arrow  3124  and, as seen in  FIG. 53B , an array of parallel, spaced, elongate optical fiber positioning elements  3126  is preferably formed, such as by conventional photolithographic techniques, over an opposite surface  3128  of substrate  3102 . It is appreciated that the positions of the array of elements  3126  on surface  3128  are preferably precisely coordinated with the positions of the electrical circuits  3120  on first surface  3122  of the substrate  3102 , as shown in  FIG. 53C .  
         [0282]     Turning to  FIG. 53D , it is seen that notches  3130  are preferably formed on surface  3128 , as by means of a dicing blade  3132 , to precisely position and accommodate alignment bore defining cylinders  3134 , as shown in  FIG. 53E .  FIG. 53E  illustrates that the centers of alignment bore defining cylinders  3134  preferably lie in the same plane as the centers  3136  of optical fibers  3108  which are precisely positioned between elements  3126  on surface  3128 .  FIG. 53F  illustrates encapsulation of the fibers  3108 , the cylinders  3134  and the positioning elements  3126  by layer  3114  of protective material, preferably epoxy.  
         [0283]     Reference is now made to Figs.  FIGS. 54A, 54B ,  54 C,  54 D,  54 E,  54 F,  54 G,  54 H,  541  and  54 J, which are simplified pictorial and sectional illustrations of a second plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B .  FIG. 54A  shows the wafer of  FIG. 53F  turned over.  
         [0284]     As shown in  FIG. 54B , a multiplicity of studs  3140 , preferably gold studs, are formed onto electrical circuits  3120  lying on surface  3122 . The studs  3140  are preferably flattened or “coined”, as shown schematically in  FIG. 54C , to yield a multiplicity of flattened electrical contacts  3142 , as shown in  FIG. 54D .  
         [0285]     As shown in  FIGS. 54E, 54F  and  54 G, the wafer of  FIG. 54D  is turned over, as indicated by an arrow  3144 , and the electrical contacts  3142  are dipped into a shallow bath  3146  of a conductive adhesive  3148 , such as H20E silver filled epoxy, manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, so as to coat the tip of each contact  3142  with adhesive  3148 , as shown. The wafer of  FIG. 54G  is then turned over, as indicated by an arrow  3150 , and a plurality of integrated circuits  3152  is mounted onto the multiplicity of contacts  3142 , as seen in  FIG. 54H . Integrated circuits  3152  may be electrical or electro-optic integrated circuits as appropriate.  
         [0286]      FIG. 54I  illustrates the application of underfill material  3154 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, at the gap between integrated circuits  3152  and electrical circuits  3120  as well as substrate  3102 . If integrated circuits  3152  include electro-optic devices, the underfill material  3154  should be transparent as appropriate.  
         [0287]     As shown in  FIG. 54J , an encapsulation layer  3156 , such as a layer of solder mask, is preferably formed over integrated circuits  3152 , electrical circuits  3120 , substrate  3102  and underfill material  3154 .  
         [0288]     For the purposes of the discussion which follows, it is assumed that at least some, if not all, of the integrated circuits  3152  are electro-optic devices. It is appreciated that additional integrated circuits (not shown) which are not electro-optic devices, may be electrically connected to the electrical circuits  3120  on substrate  3102  by other techniques, such as wire bonding.  
         [0289]     Reference is now made to Figs.  FIGS. 55A, 55B ,  55 C and  55 D, which are simplified pictorial and sectional illustrations of a third plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B .  
         [0290]      FIG. 55A  illustrates the wafer of  FIG. 54J , turned over and notched along lines extending perpendicularly to the array of optical fibers  3108 , producing an inclined cut extending entirely through at least the core  3160  of each fiber  3108  and extending at least partially through cylindrical elements  3134 .  
         [0291]      FIG. 55B  is a simplified sectional illustrations, taken along the lines LVB -LVB in  FIG. 55A , of a further stage in the production of the electro-optic integrated circuit.  
         [0292]     As shown in  FIG. 55B , the notching preferably forms a notch  3224 , at least partially overlapping the locations of the integrated circuits  3152 , at least some, if not all, of which are electro-optic devices, and extending through the layer  3114  of protective material, entirely through each optical fiber  3108  and partially into substrate  3102 . Specifically, in this embodiment, the notch  3224  extends through all of cladding  3226  of each fiber  3108  and entirely through the core  3160  of each fiber. It is appreciated that the surfaces defined by the notch  3224  are relatively rough, as shown.  
         [0293]     Turning now to  FIG. 55C , it is seen that a partially flat and partially concave mirror assembly  3230  is preferably mounted parallel to one of the rough inclined surfaces  3232  defined by notch  3224 . Mirror assembly  3230  preferably comprises a glass substrate  3234  having formed thereon a curved portion  3236  over which is formed a curved metallic layer or a dichroic filter layer  3238 . A preferred method of fabrication of mirror assembly  3230  is described hereinabove with reference to  FIGS. 19A-19E . As seen in  FIG. 55D , preferably, the mirror assembly  3230  is securely held in place partially by any suitable adhesive  3239 , such as epoxy, and partially by an optical adhesive  3240 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  3160  of the optical fibers  3108 . It is appreciated that optical adhesive  3240  may be employed throughout instead of adhesive  3239 . Optical adhesive  3240  preferably fills the interstices between the roughened surface  3232  defined by notch  3224  and a surface  3242  of mirror assembly  3230 .  
         [0294]     Reference is now made to  FIGS. 56A, 56B  and  56 C, which are enlarged simplified optical illustrations of a portion of  FIG. 55D  in accordance with preferred embodiments of the present invention.  FIG. 56A  is an enlarged simplified optical illustration of a portion of  FIG. 55D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  3250  of a core  3160 , through adhesive  3240 , substrate  3234  and curved portion  3236  to a reflective surface  3252  of layer  3238  and thence through curved portion  3236 , adhesive  3240  and substrate  3102  and layer  3104  which are substantially transparent to this light. It is noted that the index of refraction of adhesive  3240  is close to but not identical to that of curved portion  3236  and substrates  3102  and  3234 . In the embodiment of  FIG. 56A , the operation of curved layer  3238  is to focus light exiting from end  3250  of core  3160  onto the electro-optic component  3152 .  
         [0295]      FIG. 56B  is an enlarged simplified optical illustration of a portion of  FIG. 55D  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  3238  produces collimation rather than focusing of the light exiting from end  3250  of core  3160  onto the electro-optic component  3152 .  
         [0296]      FIG. 56C  is an enlarged simplified optical illustration of a portion of  FIG. 55D  in accordance with yet another embodiment of the present invention wherein a grating  3260  is added to curved layer  3238 . The additional provision of grating  3260  causes separation of light impinging thereon according to its wavelength, such that multispectral light exiting from end  3250  of core  3160  is focused at multiple locations on electro-optic component  3152  in accordance with the wavelengths of components thereof.  
         [0297]     Reference is now made to  FIG. 57 , which is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. The embodiment of  FIG. 57  corresponds generally to that described hereinabove with respect to  FIG. 55D  other than in that a mirror with multiple concave reflective surfaces is provided rather than a mirror with a single such reflective surface. As seen in  FIG. 57 , it is seen that light from an optical fiber  3316  is directed onto an electro-optic component  3320  by a partially flat and partially concave mirror assembly  3330 , preferably mounted parallel to one of the rough inclined surfaces  3332  defined by notch  3324 . Mirror assembly  3330  preferably comprises a glass substrate  3334  having formed thereon a plurality of curved portions  3336  over which are formed a curved metallic layer or a dichroic filter layer  3338 . Mirror assembly  3330  also defines a reflective surface  3340 , which is disposed on a planar surface  3342  generally opposite layer  3338 . A preferred method of fabrication of mirror assembly  3330  is described hereinabove with reference to  FIGS. 20A-20F . Preferably, the mirror assembly  3330  is securely held in place partially by any suitable adhesive  3343 , such as epoxy, and partially by an optical adhesive  3344 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  3328  of the optical fibers  3316 . It is appreciated that optical adhesive  3344  may be employed throughout instead of adhesive  3343 . The optical adhesive  3344  preferably fills the interstices between the roughened surface  3332  defined by notch  3324  and surface  3342  of mirror assembly  3330 .  
         [0298]     Reference is now made to  FIG. 58A , which is an enlarged simplified optical illustration of a portion of  FIG. 57 . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  3350  of a core  3328 , through adhesive  3344 , substrate  3334  and first curved portion  3336 , to a curved reflective surface  3352  of layer  3338  and thence through first curved portion  3336  and substrate  3334  to reflective surface  3340 , from reflective surface  3340  through substrate  3334  and second curved portion  3336  to another curved reflective surface  3354  of layer  3338  and thence through second curved portion  3336 , substrate  3334 , adhesive  3344  and substrate  3304  and layer  3305 , which are substantially transparent to this light. It is noted that the index of refraction of adhesive  3344  is close to but not identical to that of substrates  3304  and  3334 . In the embodiment of  FIG. 58A , the operation of curved layer  3338  and reflective surface  3340  is to focus light exiting from end  3350  of core  3328  onto the electro-optic component  3320 .  
         [0299]     Reference is now made to  FIG. 58B , which is an enlarged simplified optical illustration of a portion of  FIG. 57  in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  3338  produces collimation rather than focusing of the light exiting from end  3350  of core  3328  onto the electro-optic component  3320 .  
         [0300]     Reference is now made to  FIG. 58C , which is an enlarged simplified optical illustration of a portion of  FIG. 57  in accordance with yet another embodiment of the present invention wherein a reflective grating  3360  replaces reflective surface  3340 . A preferred method of fabrication of mirror assembly  3330  with grating  3360  is described hereinbelow with reference to  FIGS. 22A-22F . The additional provision of grating  3360  causes separation of light impinging thereon according to its wavelength, such that multispectral light existing from end  3350  of core  3328  is focused at multiple locations on electro-optic component  3320  in accordance with the wavelengths of components thereof.  
         [0301]     It is appreciated that, even though the illustrated embodiments of  FIGS. 55C-58C  utilize the mirror assemblies whose fabrications are described hereinabove with reference to  FIGS. 19A-20F  and  22 A- 22 G, any of the mirror assemblies whose fabrications are described hereinabove with reference to  FIGS. 18A-24G  may alternatively be utilized.  
         [0302]     Reference is now made to  FIG. 59 , which is a simplified pictorial illustration corresponding to sectional illustration  55 D.  FIG. 59  illustrates the wafer of  FIG. 55A , with partially flat and partially concave mirror assembly  3230  mounted thereon, parallel to one of the rough inclined surfaces  3232  defined by notch  3224 , as described hereinabove with reference to  FIG. 55D . It is appreciated that mirror assembly  3230  extends along the entire length of substrate  3102 .  
         [0303]     Reference is now made to  FIGS. 60A, 60B ,  60 C,  60 D,  60 E and  60 F, which are simplified pictorial and sectional illustrations of a fourth plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 52A and 52B .  FIG. 60A  shows the wafer of  FIG. 59  turned over.  FIG. 60B  is a sectional illustration of the wafer of  FIG. 60A  along lines LXB-LXB.  FIG. 60C  illustrates the formation of holes  3402  by conventional techniques, such as the use of lasers or photolithography, which communicate with electrical circuits  3120  ( FIG. 53A ) on substrate  3102 .  FIG. 60D  shows the formation of solder bumps  3404  in holes  3402 .  
         [0304]     Following the formation of solder bumps  3404  in holes  3402 , the wafer, as shown in  FIG. 60E , is preferably diced, providing a plurality of packaged electro-optic circuit chips  3406 , as illustrated in  FIG. 60F . Following dicing of substrate  3102  into a plurality of packaged electro-optic circuit chips  3406 , an optical edge surface  3407  of each of the plurality of packaged electro-optic circuit chips  3406  is polished to provide an optical quality planar surface. It is appreciated that the planar surface defined by the polishing may be either parallel, or at any suitable angle, to the plane defined by the dicing.  
         [0305]     Reference is now made to  FIG. 61 , which shows packaged electro-optic circuit chips  3406  mounted on a conventional electrical circuit board  3408  and being interconnected by a conventional optical fiber ribbon  3410  and associated conventional optical fiber connectors  3116  ( FIG. 52B ).  
         [0306]     Reference is now made to  FIG. 62 , which is a simplified pictorial illustration of an initial stage in the production of an electro-optic integrated circuit, constructed and operative in accordance with a preferred embodiment of the present invention. As seen in  FIG. 62 , one or more electrical circuits  4200  are preferably formed onto a first surface  4202  of an optional epitaxial layer  4203  of a substrate  4204 . The epitaxial layer  4203  is typically formed of silicon and has a thickness of between 2-10 microns, while the substrate  4204  is typically formed of silicon and has a thickness of 200-1000 microns. Electrical circuits  4200  are preferably formed onto substrate  4204  by conventional photolithographic and thin film processing techniques employed in the production of integrated circuits. Circuits  4200  preferably include transistors  4205  formed in layer  4203 , covered by a dielectric layer  4206 , over which is typically formed a plurality of metal conductive layers  4207  interspersed with dielectric layers  4208 , covered by a top passivation layer  4210 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands within at least part of the wavelength range of 400-1650 nm. Vias  4211 , connected to at least one conductive layer  4207 , extend through layer  4210  to the top surface  4212 .  
         [0307]     Reference is now made to  FIGS. 63A, 63B ,  63 C,  63 D and  63 E, which are simplified illustrations of the initial stages in the production of an electro optical integrated circuit in accordance with the embodiment of  FIG. 62 .  FIG. 63A  shows the substrate of  FIG. 62  after it has been turned over.  
         [0308]     As seen in  FIG. 63B , an opening  4216  is formed by removing portions of substrate  4204  at locations not underlying vias  4211 . Preferably, the entire thickness of the substrate  4204  is removed, leaving dielectric layers  4206 ,  4208 , conductive layers  4207  and top passivation layer  4210  intact. Alternatively, dielectric layer  4206  may also be removed, leaving some or all of dielectric layers  4208  and top passivation layer  4210  intact. The removal of substrate  4204  may be achieved by using conventional etching techniques and, preferably, provides a volume of dimensions of around 100 to 200 microns in width and 1000 to 3000 microns in length.  
         [0309]     As seen in  FIG. 63C , the openings  4216  are filled by a suitable transparent optical adhesive  4217 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of cores of conventionally manufactured optical fibers, commercially available from manufacturers, such as Dow Corning of the U.S.A.  
         [0310]     As seen in  FIG. 63D , conductive bumps  4218 , preferably metal bumps, such as solder bumps, are preferably formed onto the exposed surfaces of vias  4211 . As seen in  FIG. 63E , conductive bumps  4220 , preferably metal bumps, such as solder bumps, are preferably formed onto the surfaces of integrated circuit chips  4222 , which are preferably located below openings  4216 . Integrated circuit chips  4222  are in conductive engagement with vias  4211  by the soldering of bumps  4218  to bumps  4220 .  
         [0311]     Reference is now made to  FIG. 64 , which is a simplified illustration of an integrated circuit of the type referenced in  FIGS. 63A-63E , including a laser light source  4224  formed on an integrated circuit chip  4226 , located below an opening  4228  formed in an integrated circuit substrate  4230 .  
         [0312]     Reference is now made to  FIG. 65 , which is a simplified illustration of an integrated circuit of the type referenced in  FIGS. 63A-63E , including an optical detector  4232  formed on an integrated circuit chip  4234 , located below an opening  4236  formed in an integrated circuit substrate  4238 .  
         [0313]     Reference is now made to  FIG. 66 , which is a simplified illustration of an integrated circuit of the type referenced in  FIGS. 63A-63E , including multiple elements  4240  located below multiple openings  4242  formed within a substrate  4244 . These elements may by any suitable electrical or electro-optic element.  
         [0314]     Reference is now made to  FIGS. 67A, 67B ,  67 C and  67 D, which are simplified pictorial illustrations of further stages in the production of an electro-optic integrated circuit.  FIG. 67A  shows the substrate of  FIG. 62  after it has been turned over. Openings  4246  are formed on portions of substrate  4204  and filled by a transparent optical adhesive  4250 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of cores of optical fibers, commercially available from manufacturers such as Dow Corning of the U.S.A. Openings  4246  preferably extend from a second surface  4248  of substrate  4204 , which is opposite first surface  4212 , to dielectric layer  4206 . Alternatively, openings  4246  extend through dielectric layer  4206  and partially or fully through dielectric layers  4208  to passivation layer  4210 . After openings  4246  are filled with optical adhesive  4250 , multiple electro-optical elements are assembled onto integrated circuit substrate  4204 , as described hereinabove with reference to  FIGS. 63E-66 .  
         [0315]      FIG. 67B  shows an array of parallel, spaced, elongate optical fiber positioning elements  4252  that is preferably formed, such as by conventional photolithographic and etching techniques, over second surface  4248  of substrate  4204 . Preferably, positioning elements  4252  are disposed intermediate openings  4246  filled with optical adhesive  4250 .  
         [0316]     As seen in  FIG. 67C , an array of optical fibers  4256  is disposed over surface  4248  of substrate  4204 , each fiber being positioned between adjacent positioning elements  4252 . The fibers  4256  are fixed in place, relative to positioning elements  4252  and to surface  4248  of substrate  4204 , by means of a suitable adhesive  4258 , preferably epoxy, as seen in  FIG. 67D , and preferably overlie openings  4246  filled with optical adhesive  4250 .  
         [0317]     Reference is now made to  FIGS. 68A, 68B ,  68 C, and  68 D, which are simplified sectional illustrations, taken along the lines LXVIII-LXVIII in  FIG. 67D , of additional stages in the production of an electro-optic integrated circuit. As seen in  FIG. 68A , electro-optic components  4260 , such as diode lasers, are mounted onto electrical circuits  4200  ( FIG. 62 ). It is appreciated that electro-optic components  4260  may include any suitable electro-optic components, such as laser diodes, diode detectors, waveguides, array waveguide gratings or semiconductor optical amplifiers. As described hereinabove with reference to  FIG. 67A , optical opening  4246  is formed by removing portions of substrate  4204  across the entire thickness of the substrate  4204 , and filling the opening  4246  with transparent optical adhesive  4250 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of cores  4262  of the optical fibers  4256 .  
         [0318]     As shown in  FIG. 68B , a transverse notch  4264  is preferably formed, at least partially overlapping the locations of the electro-optic components  4260  and extending through the adhesive  4258 , entirely through each optical fiber  4256  and partially into both substrate  4204  and the optical adhesive  4250  in opening  4246 . Specifically, the notch  4264  extends partly through openings  4246 , defining an optical via  4266  filled with optically clear epoxy at the bottom of the notch  4264 . It is appreciated that the surfaces  4270  defined by the notch  4264  are relatively rough, as shown.  
         [0319]     Turning now to  FIG. 68C , it is seen that a partially flat and partially concave mirror  4268  is preferably mounted parallel to one of the rough inclined surfaces  4270  defined by notch  4264 . Mirror  4268  preferably comprises a glass substrate  4272  having formed thereon a curved portion  4274  over which is formed a curved metallic layer or a dichroic filter layer  4276 . As seen in  FIG. 68D , preferably, the mirror  4268  is securely held in place partially by any suitable adhesive  4278 , such as epoxy, and partially by an optical adhesive  4280 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores  4262  of the optical fibers  4256 . It is appreciated that optical adhesive  4280  may be employed throughout instead of adhesive  4278 . Optical adhesive  4280  preferably fills the interstices between the roughened surface  4270  defined by notch  4264  and a surface  4282  of mirror  4268 .  
         [0320]     Reference is now made to  FIG. 69A , which is an enlarged simplified optical illustration of a portion of  FIG. 68D . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  4284  of core  4262  of fiber  4256 , through adhesive  4280 , substrate  4272  and curved portion  4274  to a reflective surface  4286  of layer  4276  and thence through curved portion  4274 , adhesive  4280 , optical via  4266 , layers  4206 ,  4208  and  4210  which are substantially transparent to this light. It is noted that the index of refraction of adhesive  4280  is identical to that of optical via  4266  and precisely matched to the index of refraction of the core  4262 . In the embodiment of  FIG. 69A , the operation of the curved reflective surface  4286  is to focus light exiting from end  4284  of core  4262  onto the electro-optic component  4260  or similarly to focus light exiting from the electro-optic component  4260  onto the end  4284  of core  4262 .  
         [0321]     Reference is now made to  FIG. 69B , which is an enlarged simplified optical illustration of a portion of  FIG. 68D , in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  4274  produces collimation rather than focusing of the light exiting from end  4284  of core  4262  onto the electro-optic component  4260 .  
         [0322]     Reference is now made to  FIG. 69C , which is an enlarged simplified optical illustration of a portion of  FIG. 68D , in accordance with yet another embodiment of the present invention, wherein a grating  4288  is added to curved portion  4274 . The additional provision of grating  4288  causes separation of light impinging thereon according to its wavelength, such that multi-spectral light exiting from end  4284  of core  4262  is focused at multiple locations on electro-optic component  4260  in accordance with the wavelengths of components thereof.  
         [0323]     Reference is now made to  FIG. 70 , which is a simplified sectional illustration of an electro-optic integrated circuit constructed and operative in accordance with yet another preferred embodiment of the present invention. The embodiment of  FIG. 70  corresponds generally to that described hereinabove with respect to  FIG. 68D , other than in that a mirror with multiple concave reflective surfaces is provided rather than a mirror with a single such reflective surface. As seen in  FIG. 70 , light from an optical fiber  4316 , having a core  4318 , is directed onto an electro-optic component  4320  by a partially flat and partially concave mirror assembly  4330 , preferably mounted parallel to one of the rough inclined surfaces  4332  defined by a notch  4333  in a substrate  4334 .  
         [0324]     Mirror assembly  4330  preferably comprises a glass substrate  4335  having formed thereon a plurality of curved portions  4336  over which is formed a curved metallic layer or a dichroic filter layer  4338 . Mirror assembly  4330  also defines a reflective surface  4340 , which is disposed on a planar surface  4342  generally opposite layer  4338 . Preferably, the mirror assembly  4330  is securely held in place partially by any suitable adhesive  4343 , such as epoxy, and partially by an optical adhesive  4344 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of core  4318  of the optical fiber  4316  and identical to an adhesive used to fill an optical via  4346 . It is appreciated that optical adhesive  4344  may be employed throughout instead of adhesive  4343 . The optical adhesive  4344  preferably fills the interstices between the roughened surface  4332  defined by notch  4333  and surface  4342  of mirror assembly  4330 .  
         [0325]     Reference is now made to  FIG. 71A , which is an enlarged simplified optical illustration of a portion of  FIG. 70 . Here it is seen that a generally uninterrupted optical path is defined for light, preferably in the wavelength range of 400-1650 nm, from an end  4350  of core  4318 , through adhesive  4344 , substrate  4335  and first curved portion  4336 , to a curved reflective surface  4352  of layer  4338  and thence through first curved portion  4336  and substrate  4335  to reflective surface  4340 , from reflective surface  4340  through substrate  4335  and second curved portion  4336  to another curved reflective surface  4354  of layer  4338  and thence through second curved portion  4336 , substrate  4335 , adhesive  4344 , optical via  4346  and dielectric layers  4356 ,  4358  and  4360 , which are substantially transparent to this light.  
         [0326]     It is noted that the index of refraction of adhesive  4344  is close to but not identical to that of substrate  4335 . In the embodiment of  FIG. 71A , the operation of curved layer  4338  and reflective surface  4340  is to focus light exiting from end  4350  of core  4318  onto the electro-optic component  4320 .  
         [0327]     Reference is now made to  FIG. 71B , which is an enlarged simplified optical illustration of a portion of  FIG. 70 , in accordance with a further embodiment of the present invention. In this embodiment, the curvature of curved layer  4338  produces collimation rather than focusing of the light exiting from end  4350  of core  4318  onto the electro-optic component  4320 .  
         [0328]     Reference is now made to  FIG. 71C , which is an enlarged simplified optical illustration of a portion of  FIG. 70 , in accordance with yet another embodiment of the present invention, wherein a reflective grating  4362  replaces reflective surface  4340  ( FIG. 70 ). The additional provision of grating  4362  causes separation of light impinging thereon according to its wavelength, such that multi-spectral light exiting from end  4350  of core  4318  is focused at multiple locations on electro-optic component  4320  in accordance with the wavelengths of components thereof.  
         [0329]     Reference is now made to  FIGS. 72A, 72B ,  72 C,  72 D and  72 E, which are simplified pictorial illustrations of stages in the production of an electro-optic integrated circuit, constructed and operative in accordance with still another preferred embodiment of the present invention.  
         [0330]     As seen in  FIG. 72A , one or more semiconductor functional blocks  4400  are preferably formed onto a first surface  4402  of an optional epitaxial layer  4403  of a substrate  4404 . The epitaxial layer  4403  is typically formed of silicon and has a thickness of between 2-10 microns, while the substrate  4404  is typically formed of silicon and has a thickness of 200-1000 microns. Semiconductor functional blocks  4400  are preferably formed onto substrate  4404  by conventional photolithographic and thin film processing techniques employed in the production of integrated circuits. Semiconductor functional blocks  4400  preferably include transistors  4405  formed in layer  4403 , covered by a dielectric layer  4406 , over which are typically formed a plurality of metal conductive layers  4407  interspersed with dielectric layers  4408 , covered by a top passivation layer  4410 . The dielectric layers are preferably transparent to light preferably in both the visible and the infrared bands within at least part of the wavelength range of 400-1650 nin. Vias  4411 , connected to at least one conductive layer  4407 , extend through layer  4410  to the top surface  4412 . One or more semiconductor functional blocks  4400  are preferably formed on substrate  4404 .  
         [0331]      FIG. 72A  also shows locations  4414  of openings  4416  formed, as shown in  FIG. 72B , by removing portions of substrate  4404 . It is noted that locations  4414  do not underlie vias  4411 . Preferably, the entire thickness of the substrate  4404  is removed at locations  4414 , leaving dielectric layers  4406  and  4408  and conductive layers  4407  intact. Alternatively, dielectric layer  4406  may also be removed, leaving some or all of dielectric layers  4408  intact. The removal of substrate  4404  may be achieved by using conventional etching techniques and, preferably, provides a volume of dimensions of around 100 to 200 microns in width and 1000 to 3000 microns in length. The openings  4416  are filled with an optical adhesive  4418 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of the cores of optical fibers, commercially available from manufacturers such as Dow Corning of the U.S.A.  
         [0332]     As seen in  FIG. 72C , integrated circuit chips  4420  are preferably located above openings  4416 . These chips may be operatively engaged with vias (not shown) by being soldered to bumps (not shown), as illustrated for example in  FIG. 63E , thus creating an optoelectronic integrated circuit, wherein integrated circuit chips  4420  reside above the substrate of the integrated circuit.  
         [0333]     As seen in  FIG. 72D , one or more fibers  4422  are fixed underneath a bottom surface  4424  of substrate  4404 , preferably by an adhesive (not shown), similarly to that shown in  FIGS. 67C and 67D . Multiple fibers  4422  may be identical, similar or different and need not be arranged in a mutually aligned spatial relationship.  
         [0334]     As shown in  FIG. 72E , it is seen that a mirror  4430 , typically of the type illustrated in any of  FIGS. 68C-71C , is preferably mounted in operative engagement with each fiber  4422 .  
         [0335]     Reference is now made to  FIG. 73 , which is a simplified functional illustration of a preferred embodiment of the structure of  FIG. 72E . As seen in  FIG. 73 , a high frequency optical signal  4480 , typically of frequency 10 to 40 GHz, passes through an optical fiber  4482  and is reflected by a mirror  4484  through a recess  4486  onto a diode  4488 , which is located above the recess  4486 . An output electrical signal  4490  from diode  4488  may be supplied to an amplifier  4492 , which may be formed on the silicon substrate circuitry. The amplified output  4494  of amplifier  4492  may be provided to a serializer/deserializer  4496 , which may be formed on the silicon substrate circuitry.  
         [0336]     An output signal  4498  from serializer/deserializer  4496  is preferably fed to one or more semiconductor functional blocks  4500  for further processing. A laser  4502 , which may be located above a recess  4504 , may employ an electrical output  4506  from functional block  4500  to produce a modulated light beam  4508 , which is reflected by a mirror  4510  through recess  4504  to pass through a fiber  4512 . It is appreciated that electro-optic integrated circuit devices  4488  and  4502  may be configured to operate as either a light transmitter or a light receiver or both.  
         [0337]     It is appreciated that in addition to the substrate materials described hereinabove, the substrates may comprise silicon, silicon germanium, silicon on sapphire, silicon on insulator (SOI), gallium arsenide, indium phosphide or any other suitable material.  
         [0338]     Reference is now made to  FIGS. 74A, 74B ,  74 C,  74 D and  74 E, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and FIGS.  81 A-87 in accordance with one embodiment of the present invention.  FIG. 74A  shows a glass substrate  4800 , typically of thickness 200-400 microns. Substrate  4800  has formed thereon an array of microlenses  4802 , typically formed of photoresist, as seen in  FIG. 74B . The microlenses  4802  preferably have an index of refraction that is identical or very close to that of substrate  4800 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0339]     A thin metal layer  4804 , typically aluminum, is formed over the substrate  4800  and microlenses  4802  as seen in  FIG. 74C , typically by evaporation or sputtering. A glass cover layer  4806  is preferably formed over the array of microlenses  4802  and sealed thereover by an adhesive  4808  in  FIG. 74D . The substrate  4800 , the metal layer  4804  formed thereon and the glass cover layer  4806  and associated adhesive  4808  are then diced by conventional techniques, as shown in  FIG. 74E , thereby defining individual optical elements  4809 , each including a curved portion defined by microlens  4802 .  
         [0340]     Reference is now made to  FIGS. 75A, 75B ,  75 C,  75 D,  75 E and  75 F, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with another embodiment of the present invention. A glass substrate  4810 , typically of thickness 200-400 microns, seen in  FIG. 75A , has formed thereon an array of microlenses  4812 , typically formed of photoresist, as seen in  FIG. 75B . The microlenses  4812  preferably have an index of refraction that is identical or very close to that of substrate  4810 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0341]     A thin metal layer  4814 , typically aluminum, is formed over the substrate  4810  and microlenses  4812  as seen in  FIG. 75C , typically by evaporation or sputtering. A glass cover layer  4816  is preferably formed over the array of microlenses  4812  and sealed thereover by an adhesive  4818  as seen in  FIG. 75D . The substrate  4810  is then notched from underneath by conventional techniques. As seen in  FIG. 75E , notches  4819  are preferably formed at locations partially underlying microlenses  4812 .  
         [0342]     Following notching, the substrate  4810 , the microlenses  4812 , the metal layer  4814  formed thereon, the glass cover layer  4816  and the adhesive  4818  are diced by conventional techniques, as shown in  FIG. 75F , at locations intersecting inclined walls of the notches  4819 , thereby defining individual optical elements  4820 , each including a curved portion defined by part of microlens  4812 .  
         [0343]     Reference is now made to  FIGS. 76A, 76B ,  76 C,  76 D,  76 E,  76 F and  76 G, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with yet another embodiment of the present invention. A glass substrate  4821 , typically of thickness 200-400 microns, seen in  FIG. 76A , has formed thereon an array of microlenses  4822 , typically formed of photoresist, as seen in  FIG. 76B . The microlenses  4822  preferably have an index of refraction that is identical or very close to that of substrate  4821 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0344]     A thin metal layer  4824 , typically aluminum, is formed over the substrate  4821  and microlenses  4822  as seen in  FIG. 76C , typically by evaporation or sputtering. An additional metal layer  4825 , typically aluminum, is similarly formed on an opposite surface of substrate  4821 . Metal layers  4824  and  4825  are patterned typically by conventional photolithographic techniques to define respective reflective surfaces  4826  and  4827  as seen in  FIG. 76D . A glass cover layer  4828  is preferably formed over the array of microlenses  4822  and sealed thereover by an adhesive  4829  as seen in  FIG. 76E .  
         [0345]     The substrate  4821  is notched from underneath by conventional techniques. As seen in  FIG. 76F , notches  4830  need not be at locations partially underlying microlenses  4822 . Following notching, the substrate  4821 , the microlenses  4822 , the metal layers  4824  and  4825  ( FIG. 76C ), the glass cover layer  4828  and the adhesive  4829  are diced by conventional techniques, as shown in  FIG. 76G , at locations intersecting inclined walls of the notches  4830 , thereby defining individual optical elements  4831 , each including curved reflective portion  4826  defined by a pair of microlenses  4822 , as well as flat reflective surface  4827 .  
         [0346]     Reference is now made to  FIGS. 77A, 77B ,  77 C,  77 D,  77 E,  77 F and  77 G, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with still another embodiment of the present invention. A glass substrate  4832 , typically of thickness 200-400 microns, seen in  FIG. 77A , has formed thereon an array of pairs of microlenses  4833 , typically formed of photoresist, as seen in  FIG. 77B . The microlenses  4833  preferably have an index of refraction that is identical or very close to that of substrate  4832 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0347]     A thin metal layer  4834 , typically aluminum, is formed over the substrate  4832  and pairs of microlenses  4833 , as seen in  FIG. 77C , typically by evaporation or sputtering. An additional metal layer  4835 , typically aluminum, is similarly formed on an opposite surface of substrate  4832 . Metal layers  4834  and  4835  are patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  4836  and  4837  as seen in  FIG. 77D . A glass cover layer  4838  is preferably formed over the array of microlenses  4833  and sealed thereover by an adhesive  4839  as seen in  FIG. 77E .  
         [0348]     The substrate  4832  is notched from underneath by conventional techniques, defining notches  4840 , as seen in  FIG. 77F . Following notching, the substrate  4832 , the microlenses  4833 , the metal layers  4834  and  4835  ( FIG. 77C ), the glass cover layer  4838  and the adhesive  4839  are diced by conventional techniques, as shown in  FIG. 77G , at locations intersecting inclined walls of the notches  4840 , thereby defining individual optical elements  4841 , each including curved reflective surface  4836  defined by a pair of microlenses  4833 , as well as flat reflective surface  4837 .  
         [0349]     Reference is now made to  FIGS. 78A, 78B ,  78 C,  78 D,  78 E,  78 F,  78 G and  78 H, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with a further embodiment of the present invention. A glass substrate  4842 , typically of thickness 200-400 microns, seen in  FIG. 78A , has formed in an underside surface thereof an array of reflective diffraction gratings  4843 , as seen in  FIG. 78B , typically by etching. Alternatively, the gratings  4843  may be formed on the surface of the substrate  4842 , typically by lithography or transfer. An array of pairs of microlenses  4844 , typically formed of photoresist, is formed on an opposite surface of substrate  4842 , as seen in  FIG. 78C . The microlenses  4844  preferably have an index of refraction that is identical or very close to that of substrate  4842 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0350]     A thin metal layer  4845 , typically aluminum, is formed over the substrate  4842  and pairs of microlenses  4844  as seen in  FIG. 78D , typically by evaporation or sputtering. Metal layer  4845  is preferably patterned, typically by conventional photolithographic techniques, to define a reflective surface  4846 , as seen in  FIG. 78E . A glass cover layer  4847  is preferably formed over the array of microlenses  4844  and sealed thereover by an adhesive  4848  as seen in  FIG. 78F .  
         [0351]     The substrate  4842  is notched from underneath by conventional techniques, defining notches  4849 , as seen in  FIG. 78G . Following notching, the substrate  4842 , the microlenses  4844 , the metal layer  4845  ( FIG. 78D ), the glass cover layer  4847  and the adhesive  4848  are diced by conventional techniques, as shown in  FIG. 78H , at locations intersecting inclined walls of the notches  4849 , thereby defining individual optical elements  4850 , each including curved reflective portion  4846  defined by a pair of microlenses  4844  as well as flat reflective grating  4843 .  
         [0352]     Reference is now made to  FIGS. 79A, 79B ,  79 C,  79 D,  79 E,  79 F,  79 G and  79 H, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with yet a further embodiment of the present invention. A glass substrate  4851 , typically of thickness 200-400 microns, seen in  FIG. 79A , has formed in an underside surface thereof an array of reflective diffraction gratings  4852 , as seen in  FIG. 79B , typically by etching. Alternatively, the gratings  4852  may be formed on the surface of the substrate  4851 , typically by lithography or transfer. An array of pairs of microlenses  4853 , typically formed of photoresist, is formed on an opposite surface of substrate  4851 , as seen in  FIG. 79C . The microlenses  4853  preferably have an index of refraction that is identical or very close to that of substrate  4851 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0353]     A thin metal layer  4854 , typically aluminum, is formed over the substrate  4851  and pairs of microlenses  4853  as seen in  FIG. 79D , typically by evaporation or sputtering. An additional metal layer  4855  is similarly formed on an opposite surface of the substrate  4851 . Metal layers  4854  and  4855  are preferably patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  4856  and  4857 , as seen in  FIG. 79E . A glass cover layer  4858  is preferably formed over the array of microlenses  4853  and sealed thereover by an adhesive  4859  as seen in  FIG. 79F .  
         [0354]     The substrate  4851  is notched from underneath by conventional techniques, defining notches  4860 , as seen in  FIG. 79G . Following notching, the substrate  4851 , the microlenses  4853 , the metal layers  4854  and  4855  ( FIG. 79D ), the glass cover layer  4858  and the adhesive  4859  are diced by conventional techniques, as shown in  FIG. 79H , at locations intersecting inclined walls of the notches  4860 , thereby defining individual optical elements  4861 , each including curved reflective surface  4856  defined by a pair of microlenses  4853  as well as flat reflective grating  4852  and flat reflective surfaces  4857 .  
         [0355]     Reference is now made to  FIGS. 80A, 80B ,  80 C,  80 D,  80 E,  80 F,  80 G and  80 H, which are simplified illustrations of a method for fabricating optical elements employed in the embodiments of  FIGS. 62-73  and  FIGS. 81A-87  in accordance with still a further embodiment of the present invention. A glass substrate  4862 , typically of thickness 200-400 microns, seen in  FIG. 80A , has formed therein an array of reflective diffraction gratings  4863 , as seen in  FIG. 80B , typically by etching. Alternatively, the gratings  4863  may be formed on the surface of the substrate  4862 , typically by lithography or transfer. An array of microlenses  4864 , typically formed of photoresist, is formed on the same surface of substrate  4862 , as seen in  FIG. 80C . The microlenses  4864  preferably have an index of refraction which is identical or very close to that of substrate  4862 . The microlenses may be formed by one or more conventional techniques, such as photolithography and thermal reflow, photolithography using of a grey scale mask, jet printing and pattern transfer onto the substrate by etching.  
         [0356]     A thin metal layer  4865 , typically aluminum, is formed over the substrate  4862  and microlenses  4864  as seen in  FIG. 80D , typically by evaporation or sputtering. An additional metal layer  4866  is similarly formed on an opposite surface of the substrate  4862 . Metal layers  4865  and  4866  are preferably patterned, typically by conventional photolithographic techniques, to define respective reflective surfaces  4867  and  4868 , as seen in  FIG. 80E . A glass cover layer  4869  is preferably formed over the array of microlenses  4864  and sealed thereover by an adhesive  4870  as seen in  FIG. 80F .  
         [0357]     The substrate  4862  is notched from underneath by conventional techniques, defining notches  4871 , as seen in  FIG. 80G . Following notching, the substrate  4862 , the microlenses  4864 , the metal layers  4865  and  4866  ( FIG. 80D ), the glass cover layer  4869  and the adhesive  4870  are diced by conventional techniques, as shown in  FIG. 80H , at locations intersecting inclined walls of the notches  4871 , thereby defining individual optical elements  4872 , each including curved reflective surface  4867  defined by microlens  4864  as well as flat reflective grating  4863  and a flat reflective surface  4868 .  
         [0358]     Reference is now made to  FIGS. 81A and 81B , which are simplified pictorial illustrations of a packaged electro-optic integrated circuit  5100 , having integrally formed therein an optical connector and electrical connections, alone and in conjunction with a conventional optical connector.  
         [0359]     As seen in  FIGS. 81A and 81B , a packaged electro-optic integrated circuit  5100  is provided in accordance with a preferred embodiment of the present invention, preferably in accordance with the teachings presented hereinabove with reference to  FIGS. 1A-51  and  62 - 80 H, and includes a semiconductor substrate  5102 , typically silicon, silicon germanium, gallium arsenide or indium phosphide. Electrical circuitry (not shown) is formed, as by conventional photolithographic and thin film processing techniques generally used for the manufacturing production of CMOS and other integrated circuits, over one surface of substrate  5102  and is encapsulated by a layer  5104  of a protective material such as silicon dioxide, silicon nitride, silicon oxy-nitride, or BCB, commercially available from Dow Corning of the U.S.A., or any other suitable passivation layer. An array  5106  of electrical connections, preferably in the form of conventional solder bumps, communicates with the electrical circuitry via conductive pathways (not shown) extending through the protective material of layer  5104 .  
         [0360]     Formed on a surface of substrate  5102  opposite to that adjacent layer  5104  there are defined optical pathways (not shown) which communicate with an array of optical fibers  5108 , whose ends are aligned along an edge  5110  of the substrate  5102 . Preferably, physical alignment bores  5112  are aligned with the array of optical fibers  5108 . The bores  5112  are preferably defined by cylindrical elements, which, together with the optical fibers  5108  and the optical pathways, are encapsulated by a layer  5114  of protective material, preferably epoxy.  
         [0361]      FIG. 81B  shows a conventional MT type optical connector  5116 , such as an MT connector manufactured by SENKO Advanced Components, Inc. of Marlborough, Mass., USA, arranged for mating contact with the packaged electro-optic circuit  5100 , wherein alignment pins  5118  of connector  5116  are arranged to seat in alignment bores  5112  of the electro-optic circuit  5100 . Optical fiber ends (not shown) of connector  5116  are arranged in butting aligned relationship with the ends of the array  5108  of optical fibers in packaged electro-optic circuit  5100 .  
         [0362]     Reference is now made to  FIGS. 82A, 82B ,  82 C,  82 D,  82 E,  82 F and  82 G, which are simplified pictorial and sectional illustrations of a plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B . Turning to  FIG. 82A , it is seen that electrical circuits  5120  are preferably formed onto a first surface  5122  of substrate  5102 . Substrate  5102  is preferably of thickness between 200-1000 microns. The electrical circuits  5120  are preferably formed by conventional photolithographic and other thin film techniques employed in the production of CMOS and other integrated circuits.  
         [0363]     The substrate shown in  FIG. 82A  is turned over, as indicated by an arrow  5124 , and as shown in  FIG. 82B , an array of holes  5125  extending partially or totally through the semiconductor substrate  5102  is formed, such as by conventional photolithographic techniques, on a second surface  5128 , opposite surface  5122  of substrate  5102 . Following an etching process, the holes are filled with an optical adhesive (not shown), such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, whose refractive index preferably is precisely matched to that of cores of conventionally manufactured optical fibers. This results in an array of optical vias, formed as described hereinabove with reference to  FIGS. 63A-63C , through the substrate  5102 , which are transparent to light within at least part of the wavelength range of 400-1650 nm.  
         [0364]     As shown in  FIG. 82C , an array of parallel, spaced, elongate optical fiber positioning elements  5126  is preferably formed, such as by conventional photolithographic techniques, over second surface  5128  of substrate  5102 . Turning to  FIG. 82D , which is a simplified sectional illustration taken along the lines LXXXIID-LXXXIID in  FIG. 82C , it is appreciated that the positions of the arrays of optical adhesive filled holes  5125  and positioning elements  5126  on surface  5128  are preferably precisely coordinated with the positions of the electrical circuits  5120  on first surface  5122  of the substrate  5102 .  
         [0365]     Turning to  FIG. 82E , it is seen that notches  5130  are preferably formed on surface  5128 , as by means of a dicing blade  5132 , to precisely position and accommodate alignment bore defining cylinders  5134 , as shown in  FIG. 82F .  FIG. 82F  illustrates that the centers of alignment bore defining cylinders  5134  preferably lie in the same plane as the centers  5136  of optical fibers  5108  which are precisely positioned between elements  5126  on surface  5128 .  FIG. 82G  illustrates encapsulation of the fibers  5108 , the cylinders  5134  and the positioning elements  5126  by layer  5114  of protective material, preferably epoxy.  
         [0366]     Reference is now made to  FIGS. 83A, 83B ,  83 C,  83 D and  83 E, which are simplified pictorial and sectional illustrations of a further plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B .  FIG. 83A  shows the wafer of  FIG. 82G  turned over.  
         [0367]      FIG. 83B  is a sectional illustration of the wafer of  FIG. 83A  along lines LXXXIIIB-LXXXIIIB. As shown in  FIG. 83B , a multiplicity of bumps  5140 , preferably gold or solder bumps, are formed onto electrical circuits  5120  lying on surface  5122 .  
         [0368]     A plurality of integrated circuits  5152  are mounted onto the multiplicity of bumps  5140  by standard flip chip attachment techniques, as seen in  FIG. 83C . Integrated circuits  5152  may be electrical or electro-optic integrated circuits, as appropriate.  
         [0369]      FIG. 83D  illustrates the application of underfill material  5154 , such as OG  146 , manufactured by Epoxy Technology, 14 Fortune Drive, Billerica, Mass. 01821, USA, at the gap between integrated circuits  5152  and electrical circuits  5120  as well as substrate  5102 . If integrated circuits  5152  include electro-optic devices, the underfill material  5154  should be transparent as appropriate.  
         [0370]     As shown in  FIG. 83E , an encapsulation layer  5156 , such as a layer of BCB or solder mask or other encapsulating material, is preferably formed over integrated circuits  5152 , electrical circuits  5120 , substrate  5102  and underfill material  5154 .  
         [0371]     For the purposes of the following discussion, it is assumed that at least some, if not all, of the integrated circuits  5152  are electro-optic devices. It is appreciated that additional integrated circuits (not shown), which are not electro-optic devices, may be electrically connected to the electrical circuits  5120  on substrate  5102  either by flip chip or by other techniques, such as wire bonding.  
         [0372]     Reference is now made to  FIG. 84  which is a simplified pictorial illustration corresponding to sectional illustration  68 B.  
         [0373]      FIG. 84  illustrates the wafer of  FIG. 83E , turned over and notched along lines extending perpendicularly to the array of optical fibers  5108 , producing notches  5160 , which have an inclined cut  5162 , extending entirely through at least a core  5164  of each fiber  5108  and extending at least partially through cylindrical elements  5134  and optical adhesive filled holes  5125 .  
         [0374]     Reference is now made to  FIG. 85 , which is a simplified pictorial illustration corresponding to sectional illustrations of  FIGS. 68C, 68D  and  70 .  FIG. 85  illustrates the wafer of  FIG. 84 , with partially flat and partially concave mirror assembly  5230  mounted thereon, parallel to one of the inclined cuts  5162  defined by notch  5160 , as described hereinabove with reference to  FIG. 84 . It is appreciated that mirror assembly  5230  extends along the entire length of substrate  5102 .  
         [0375]     Reference is now made to  FIGS. 86A, 86B ,  86 C,  86 D,  86 E and  86 F, which are simplified pictorial and sectional illustrations of a further plurality of stages in the manufacture of the packaged electro-optic circuit of  FIGS. 81A and 81B .  FIG. 86A  shows the wafer of  FIG. 85  turned over.  FIG. 86B  is a sectional illustration of the wafer of  FIG. 86A  along lines LXXXVIB-LXXXVIB.  FIG. 86C  illustrates the formation of holes  5402  by conventional techniques, such as the use of lasers or photolithography, which communicate through layer  5156  with electrical circuits  5120  on substrate  5102 .  FIG. 86D  shows the formation of solder bumps  5404  in holes  5402 .  
         [0376]     Following the formation of solder bumps  5404  in holes  5402 , the wafer, a section of which is shown in  FIG. 86E , is preferably diced, providing a plurality of packaged electro-optic circuit chips  5406 , as illustrated in  FIG. 86F . Following dicing of substrate  5102  into a plurality of packaged electro-optic circuit chips  5406 , an optical edge surface  5407  of each of the plurality of packaged electro-optic circuit chips  5406  is polished to provide an optical quality planar surface. It is appreciated that the planar surface defined by the polishing may be either parallel to the plane defined by the dicing, or at any suitable angle.  
         [0377]     Reference is now made to  FIG. 87 , which shows packaged electro-optic integrated circuit chips  5406  mounted on a conventional electrical circuit board  5408  and being interconnected by a conventional optical fiber ribbon  5410  and associated conventional optical fiber connectors  5116 .  
         [0378]     It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and sub combinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.