Abstract:
This invention discloses an optical device including at least one first substrate defining a multiplicity of optical fiber positioning grooves, a multiplicity of optical fibers fixed in each of said multiplicity of optical fiber positioning grooves on the at least one first substrate, whereby the multiplicity of optical fibers lie in an optical fiber plane and the ends of each of the multiplicity of optical fibers lie substantially in a first predetermined arrangement in the optical fiber plane,a second substrate fixed onto the at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, a lens assembly including a third substrate, and a lens fixed onto the third substrate, the lens assembly being mounted onto the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers.

Description:
FIELD OF THE INVENTION 
     The present invention relates to integrated optical devices generally and more particularly to packaging of integrated optical devices. 
     BACKGROUND OF THE INVENTION 
     Various types of integrated optical devices are known. It is well known to pigtail an optical fiber onto an integrated optical device. Difficulties arise, however, when it is sought to pigtail multiple optical fibers onto integrated optical devices. When the optical modes in waveguides and optical fibers are similar, it is conventional to pigtail them by suitable alignment and butt coupling in an integrated optical device. 
     When there exists a substantial disparity in the respective optical modes of the optical fibers and the waveguides, optical elements must be employed to enable successful pigtailing. Particularly when the optical modes are relatively small, very high alignment accuracy is required in the alignment of three elements, the waveguide, the optical element and the fiber. 
     The following patents are believed to representative of the present state of the art: U.S. Pat. Nos. 5,737,138; 5,732,181; 5,732,173; 5,721,797; 5,712,940; 5,712,937; 5,703,973; 5,703,980; 5,708,741; 5,706,378; 5,611,014; 5,600,745; 5,600,741; 5,579,424; 5,570,442; 5,559,915; 5,907,649; 5,898,806; 5,892,857; 5,881,190; 5,875,274; 5,867,619; 5,859,945; 5,854,868; 5,854,867; 5,828,800; 5,793,914; 5,784,509; 5,835,659; 5,656,120; 5,482,585; 5,482,585; 5,625,726; 5,210,800; and 5,195,154. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a cost-effective and reliable integrated optics packaging technique and optical devices constructed thereby. 
     There is thus provided in accordance with a preferred embodiment of the present invention an optical device including at least one first substrate defining a multiplicity of optical fiber positioning grooves, a multiplicity of optical fibers fixed in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, whereby the multiplicity of optical fibers lie in an optical fiber plane and the ends of each of the multiplicity of optical fibers lie substantially in a first predetermined arrangement in the optical fiber plane, a second substrate fixed onto the at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, a lens assembly including a third substrate, and a lens fixed onto the third substrate, the lens assembly being mounted onto the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, whereby the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in a plane perpendicular to the optical fiber plane to a first degree of accuracy and the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in the optical fiber plane to a second degree of accuracy, less than the first degree of accuracy. 
     Further in accordance with a preferred embodiment of the present invention the at least one first substrate comprises a pair of first substrates having the optical fiber positioning grooves thereon arranged in mutually facing relationship. 
     Still further in accordance with a preferred embodiment of the present invention the lens comprises a cylindrical lens which extends along a cylindrical lens axis. Preferably the cylindrical lens axis lies parallel to the optical fiber plane. 
     Additionally in accordance with a preferred embodiment of the present invention the third substrate is fixed in engagement with the edge of the second substrate by an adhesive. Preferably the third substrate is fixed in engagement with the edge of the second substrate by an adhesive. 
     Additionally in accordance with a preferred embodiment of the present invention the multiplicity of optical fiber positioning grooves are mutually parallel. Preferably the multiplicity of optical fiber positioning grooves are arranged in a fan arrangement in order to compensate for optical aberrations. 
     There is also provided in accordance with a preferred embodiment of the present invention a method for producing an optical device including the steps of forming a multiplicity of optical fiber positioning grooves on at least one first substrate, placing each of a multiplicity of optical fibers in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, retaining each of the multiplicity of optical fibers in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, such that the multiplicity of optical fibers lie in an optical fiber plane, precisely defining the ends of each of the multiplicity of optical fibers so that they all lie substantially in a first predetermined arrangement, fixing a second substrate onto the at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, fixing a lens onto a third substrate, precisely aligning the third substrate in engagement with the edge of the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, and fixing the third substrate in engagement with said edge of the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, whereby the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in a plane perpendicular to the optical fiber plane to a first degree of accuracy and the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in the optical fiber plane to a second degree of accuracy, less than the first degree of accuracy. Preferably the step of fixing the third substrate in engagement with the edge employs an adhesive and the step of precisely aligning the third substrate in engagement with the edge of the second substrate employs an external positioner. 
     Further in accordance with a preferred embodiment of the present invention the at least one first substrate includes a pair of first substrates having the optical fiber positioning grooves thereon arranged in mutually facing relationship. 
     Additionally or alternatively the lens includes a cylindrical lens which extends along a cylindrical lens axis. Preferably the precisely aligning step and the fixing step arrange the cylindrical lens such that the cylindrical lens axis lies parallel to the optical fiber plane. 
     Preferably the multiplicity of optical fiber positioning grooves are mutually parallel. 
     Alternatively accordance with a preferred embodiment of the present invention the multiplicity of optical fiber positioning grooves are arranged in a fan arrangement in order to compensate for optical aberrations. 
     There is further provided in accordance with a preferred embodiment of the present invention an optical device including at least one optical substrate having formed thereon at least one waveguide, at least one base substrate onto which the at least one optical substrate is fixed, and at least one optical module, precisely positioned onto each at least one base substrate and fixed thereto by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one module and the at least one waveguide. 
     Further in accordance with a preferred embodiment of the present invention the at least one optical module includes a lens or includes a cylindrical lens, and at least one optical fiber. 
     Preferably the at least one optical module also includes a lens which is operative to couple light from the at least one fiber to the at least one waveguide and also including the step of positioning output optics including at least one output fiber on the at least one base substrate so as to receive light from the at least one waveguide. Additionally or alternatively the lens is operative to couple light from a first number of fibers to a greater number of waveguides. 
     Additionally in accordance with a preferred embodiment of the present invention the at least one waveguide includes stacking a plurality of base substrates each having mounted thereon at least one optical substrate having formed thereon at least one waveguide and wherein the step of positioning the output optics includes arranging at least one lens to receive light from waveguides formed on multiple ones of the plurality of optical substrates. Preferably the step of positioning the output optics includes employing side mounting blocks thereby to preserve precise mutual alignment of said at least one lens and the at least one waveguide. 
     Still further in accordance with a preferred embodiment of the present invention the step of positioning output optics includes employing side mounting blocks thereby to preserve precise mutual alignment of said at least one lens and said at least one waveguide, and the at least one waveguide includes a multiplicity of waveguides. The step of positioning the output optics includes positioning at least one lens so as to receive light from multiple ones of the multiplicity of waveguides. Still further in accordance with a preferred embodiment of the present invention the lens is operative to couple light from a first number of fibers to an identical number of waveguides. Preferably the first number of waveguides comprises at least one waveguide. 
     Still further in accordance with a preferred embodiment of the present invention the at least one optical substrate is a light deflector. 
     Additionally in accordance with a preferred embodiment of the present invention, the optical device includes output optics receiving light from the at least one waveguide and including at least one output fiber. 
     Additionally or alternatively the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. The at least one optical substrate may be a light deflector and preferably the at least one optical substrate is formed of gallium arsenide. 
     Still further in accordance with a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides and wherein the output optics includes at least one lens receiving light from multiple ones of the multiplicity of waveguides. Additionally or alternatively the output optics includes at least one lens receiving light from waveguides formed on multiple ones of the plurality of optical substrates. Furthermore the at least one optical substrate may be a light deflector. 
     The output optics may also include at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. 
     Additionally or preferably the at least one optical substrate is formed of gallium arsenide. 
     Still further in accordance with a preferred embodiment of the present invention the optical module includes at least one first substrate defining a multiplicity of optical fiber positioning grooves, a multiplicity of optical fibers fixed in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, whereby the multiplicity of optical fibers lie in an optical fiber plane. The ends of each of the multiplicity of optical fibers may lie substantially in a first predetermined arrangement in the optical fiber plane. A second substrate is preferably fixed on at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, a lens assembly including a third substrate, and a lens fixed onto the third substrate, the lens assembly being mounted onto the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers. The separation between the lens and the ends of each of the multiplicity of optical fibers may be defined in a plane perpendicular to the optical fiber plane to a first degree of accuracy and the separation between the lens and the ends of each of the multiplicity of optical fibers may be defined in the optical fiber plane to a second degree of accuracy, less than the first degree of accuracy. 
     Further in accordance with a preferred embodiment of the present invention the lens includes a cylindrical lens. 
     Additionally in accordance with a preferred embodiment of the present invention also including output optics receiving light from the at least one waveguide and including at least one output fiber. Additionally or alternatively the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. Preferably the at least one optical substrate is a light deflector and the at least one optical substrate is formed of gallium arsenide. 
     Further in accordance with a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides and wherein the output optics includes at least one lens receiving light from multiple ones of the multiplicity of waveguides. Additionally or alternatively the multiplicity of waveguides is formed on a plurality of optical substrates and the output optics includes at least one lens receiving light from waveguides formed on multiple ones of the plurality of optical substrates. 
     Preferably the at least one optical substrate is a light deflector and the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. The at least one optical substrate may be formed of gallium arsenide. 
     There is also provided in accordance with a preferred embodiment of the present invention an optical device including at least one optical substrate having formed thereon at least one waveguide having a center which lies in a waveguide plane, a base substrate onto which the at least one optical substrate is fixed and defining at least one optical fiber positioning groove, and at least one optical fiber fixed in the at least one optical fiber positioning groove on the base substrate, whereby a center of the at least one optical fiber lies in a plane which is substantially coplanar with the waveguide plane. 
     Preferably electrical connections are mounted on the base substrate. 
     Additionally the at least one optical module is precisely positioned onto the base substrate and fixed thereto by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one module and the at least one waveguide. 
     Additionally or alternatively the at least one optical substrate is a light deflector. 
     There is further provided in accordance with a preferred embodiment of the present invention a method for producing an optical device including the steps of forming at least one waveguide onto at least one optical substrate, mounting the at least one optical substrate onto at least one base substrate, and precisely positioning at least one optical module onto the base substrate, including employing side mounting blocks thereby to preserve precise mutual alignment of the at least one module and the at least one waveguide. 
     Additionally or alternatively the at least one optical module comprises a lens which is preferably a cylindrical lens. 
     Further in accordance with a preferred embodiment of the present invention the at least one optical module includes at least one optical fiber. Additionally or alternatively the at least one optical module also includes a lens which is operative to couple light from the at least one fiber to the at least one waveguide. Preferably the lens is operative to couple light from a first number of fibers to a greater number of waveguides. 
     Alternatively the lens is operative to couple light from a first number of fibers to an identical number of waveguides. 
     Additionally in accordance with a preferred embodiment of the present invention the first number of waveguides includes at least one waveguide. 
     Still further in accordance with a preferred the at least one optical substrate is a light deflector. 
     Additionally in accordance with a preferred embodiment of the present invention, the method for producing an optical device also includes the steps of providing output optics receiving light from the at least one waveguide and including at least one output fiber. Furthermore, the output optics may include at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. Additionally or alternatively the at least one optical substrate is a light deflector. Preferably the at least one optical substrate is formed of gallium arsenide. 
     Still further in accordance with a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides and wherein the output optics includes at least one lens receiving light from multiple ones of the multiplicity of waveguides. 
     Further in accordance with a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides formed on a plurality of optical substrates and wherein the output optics includes at least one lens receiving light from waveguides formed on multiple ones of the plurality of optical substrates. Additionally or alternatively the at least one optical substrate is a light deflector. Preferably the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. Preferably the at least one optical substrate is formed of gallium arsenide. 
     Still further in accordance with a preferred embodiment of the present invention the optical module includes at least one first substrate defining a multiplicity of optical fiber positioning grooves, a multiplicity of optical fibers fixed in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, whereby the multiplicity of optical fibers lie in an optical fiber plane and the ends of each of the multiplicity of optical fibers lie substantially in a first predetermined arrangement in the optical fiber plane, a second substrate fixed onto the at least one first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, a lens assembly including a third substrate, and a lens fixed onto the third substrate, the lens assembly being mounted onto the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, whereby the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in a plane perpendicular to the optical fiber plane to a first degree of accuracy and the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in the optical fiber plane to a second degree of accuracy, less than the first degree of accuracy. 
     Additionally or alternatively the lens includes a cylindrical lens. Preferably the at least one optical substrate is a light deflector. 
     Additionally in accordance with a preferred embodiment of the present invention and also including providing output optics receiving light from said at least one waveguide and including at least one output fiber. Additionally or alternatively the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. The at least one optical substrate may be a light deflector and preferably the at least one optical substrate is formed of gallium arsenide. 
     Still further according to a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides and wherein the output optics includes at least one lens receiving light from multiple ones of the multiplicity of waveguides. 
     Further in accordance with a preferred embodiment of the present invention the at least one waveguide includes a multiplicity of waveguides formed on a plurality of optical substrates and wherein the output optics includes at least one lens receiving light from waveguides formed on multiple ones of the plurality of optical substrates. Preferably the at least one optical substrate is a light deflector. 
     Additionally in accordance with a preferred embodiment of the present invention the output optics includes at least one lens fixed onto the base substrate by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one lens and the at least one waveguide. Preferably the at least one optical substrate is formed of gallium arsenide. 
     There is also provided in accordance with yet another preferred embodiment of the present invention a method including forming on at least one optical substrate at least one waveguide having a center which lies in a waveguide plane, fixing the at least one optical substrate onto a base substrate and defining on the base substrate at least one optical fiber positioning groove, and fixing at least one optical fiber in the at least one optical fiber positioning groove on the base substrate, whereby a center of the at least one optical fiber lies in a plane which is substantially coplanar with the waveguide plane. 
     Preferably electrical connections are mounted on the base substrate. 
     Additionally the at least one optical module is precisely positioned onto the base substrate and fixed thereto by means of side mounting blocks thereby to preserve precise mutual alignment of the at least one module and the at least one waveguide. 
     Still further in accordance with a preferred embodiment of the present invention the at least one optical substrate is a light deflector. Preferably also including mounting electrical connections on said base substrate. 
     There is further provided in accordance with another preferred embodiment of the present invention a method for producing an optical device including the steps of lithographically forming a multiplicity of waveguides onto an optical substrate, mounting the optical substrate onto a base substrate, and precisely positioning a fiber optic module, having a multiplicity of optical fiber ends and an optical mode modifying lens, onto the base substrate, including using at least one external positioner, manipulating at least one of the fiber optic module and the base substrate relative to the other such that the mode of each optical fiber matches the mode of at least one corresponding waveguide with relatively low light loss, and fixing the fiber optic module in a desired relative position on the base substrate independently of the external positioner, and disengaging the at least one external positioner from the modulated light source. 
     Further in accordance with a preferred embodiment of the present invention the step of fixing includes employing side mounting blocks to fix the module in position on the base substrate upon precise mutual alignment of the module and the multiplicity of waveguides. 
     Still further in accordance with a preferred embodiment of the present invention also including the step of producing a fiber optic module which includes the steps of forming a multiplicity of optical fiber positioning grooves on at least one first substrate, placing each of a multiplicity of optical fibers in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, retaining each of the multiplicity of optical fibers in each of the multiplicity of optical fiber positioning grooves on the at least one first substrate, such that the multiplicity of optical fibers lie in an optical fiber plane, precisely defining the ends of each of the multiplicity of optical fibers so that they all lie substantially in a first predetermined arrangement, fixing a second substrate onto the first substrate such that an edge of the second substrate extends beyond the ends of each of the multiplicity of optical fibers, fixing a lens onto a third substrate, precisely aligning the third substrate in engagement with the edge of the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, and fixing the third substrate in engagement with the edge of the second substrate such that the lens lies in a second predetermined arrangement with respect to the ends of each of the multiplicity of optical fibers, whereby the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in a plane perpendicular to the optical fiber plane to a first degree of accuracy and the separation between the lens and the ends of each of the multiplicity of optical fibers is defined in the optical fiber plane to a second degree of accuracy, less than the first degree of accuracy. 
     Preferably the optical substrate is gallium arsenide and the optical device functions as a switch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
     FIGS. 1A-1I are simplified pictorial illustrations of a method for producing an optical fiber module in accordance with a preferred embodiment of the present invention; 
     FIGS. 2A-2C are simplified pictorial illustrations of three alternative embodiments of a method for mounting an active integrated optics waveguide assembly onto a base substrate which are useful in the present invention; 
     FIGS. 3A-3F are simplified pictorial illustrations of a method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with a preferred embodiment of the present invention corresponding to FIGS. 2A and 2B; 
     FIGS. 4A-4F are simplified pictorial illustrations of a method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with another preferred embodiment of the present invention corresponding to the embodiment of FIG. 2C; 
     FIGS. 5A-5F are simplified pictorial illustrations of a method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with yet another preferred embodiment of the present invention corresponding to the embodiment of FIG. 2C; 
     FIGS. 6A-6E are simplified pictorial illustrations of a method for associating output optics with the optical device of 
     FIG. 3F in accordance with a preferred embodiment of the present invention; 
     FIGS. 7A-7D are simplified pictorial illustrations of a method for constructing an integrated optics optical fiber switch using a plurality of base substrates bearing integrated optics waveguide assemblies and optical fiber modules as shown in FIG. 3F; 
     FIGS. 8A-8D are simplified pictorial illustrations of a method for associating output optics with the optical device of FIG. 4F in accordance with a preferred embodiment of the present invention; 
     FIGS. 9A-9D are simplified pictorial illustrations of a method for constructing an integrated optics optical fiber switch using a plurality of base substrates bearing integrated optics waveguide assemblies and optical fiber modules as shown in FIG.  4 F. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to FIGS. 1A-1I, which are simplified pictorial illustrations of a method for producing an optical fiber module in accordance with a preferred embodiment of the present invention. The method preferably begins with the provision of a V-grooved substrate, such as substrate  10  in FIG. 1A or substrate  12  in FIG.  1 B. The substrate is typically silicon, but may alternatively be silica, glass or any other suitable material. 
     The V-grooves may be parallel as shown in FIG. 1A at reference numeral  14  or non-parallel as shown in FIG. 1B at reference numeral  16 . The description that follows refers to a parallel orientation, it being understood that a non-parallel orientation may be employed instead. 
     Preferably, the V-grooves are formed by lithography or by grinding. The accuracy of the dimensions of the V-grooves is preferably to a fraction of a micron, such that when optical fibers  20  are secured in the V-grooves  22  formed in a substrate  24 , as shown in FIG. 1C, their relative alignment is within one-half micron in two dimensions. 
     Following placement of the optical fibers  20  in V-grooves  22 , as shown in FIG. 1C, the fibers are secured in position by a cover element  26 , as shown in FIG.  1 D. The cover element  26  may be identical to the V-grooved substrate  24  in an upside down orientation. 
     It is appreciated that the ends of the optical fibers  20  may all be suitably aligned at the time of their placement in the V-grooves. Preferably, however, this alignment is not required and following placement of the fibers and securing thereof in the V-grooves  22 , the fiber ends are cut and polished together with substrate  24  and cover element  26  such that the fiber ends lie in the same plane as the edge of the substrate  24  and cover  26 . In FIG. 1D, this plane is indicated by reference numeral  28 . 
     Preferably, suitable adhesive is employed both at the stages shown in FIGS. 1C and 1D to retain the fibers in place and subsequently to hold the cover element  26  onto substrate  24  in secure engagement with fibers  20 . 
     As seen in FIG. 1E, a sheet of glass  30  or any other suitable substrate, which is preferably transparent for ease of alignment, is aligned with cover element  26  such that at least one edge  32  thereof lies in highly accurate parallel alignment with plane  28 , and separately therefrom by a precisely determined distance. The substrate  30  is then fixed onto cover element  26 , as by means of a UV curable adhesive  27  and a UV light source  29 , as shown in FIG.  1 F. 
     Referring now to FIG. 1G, a lens  40 , preferably a cylindrical lens, which is mounted onto a mounting substrate  42 , is aligned with respect to edge  32  of substrate  30 . This alignment is preferably provided to a high degree of accuracy, to the order of one-half micron, by means of a vacuum engagement assembly  44  connected to a suitable positioner, not shown, such as Melees Grist Nanoblock. This degree of accuracy is greater than that required in the parallelism and separation distance between edge  32  and plane  28 . As seen in FIG. 1H, the substrate  42  is then fixed onto edge  32  of substrate  30 , as by means of a UV curable adhesive  41  and the UV light source  29 . 
     FIG. 1I illustrates the resulting optical relationship between the optical modes  50  of the fibers  20 , which are seen to be circular upstream of lens  40  and the optical modes  52  downstream of the lens  40 , which are seen to be highly elliptical. It is appreciated that it is a particular advantage of the present invention that the highly elliptical modes which are produced by lens  40  are very similar to whose in integrated optical waveguides, as is described in applicant&#39;s published PCT application WO 98/59276. Furthermore, the arrangement described hereinabove produces a mode from a single fiber which is sufficiently highly elliptical so that it may be coupled to a multiplicity of waveguides arranged side by side, as described in applicant&#39;s published PCT application WO 98/59276, the contents of which are hereby incorporated by reference. It is appreciated that in accordance with a preferred embodiment of the present invention, lens  40  may couple a single fiber to a single waveguide or to multiple waveguides. 
     Reference is now made to FIG. 2A-2C, which are simplified pictorial illustrations of three alternative embodiments of a method for mounting an active integrated optics waveguide assembly onto a base substrate which is useful in the present invention. 
     FIG. 2A illustrates flip-chip type mounting of an integrated optics waveguide device  100 , such as a waveguide device described and claimed in applicant&#39;s published PCT application WO 98/59276, the disclosure of which is hereby incorporated by reference. Device  100  is preferably embodied in a flip-chip package, such as that described in FIG. 31 of applicant&#39;s published PCT application WO 98/59276. In this embodiment, device  100  is mounted onto an integrated electronic circuit  102 , such as an ASIC. 
     FIG. 2B illustrates conventional wire bond type mounting of an integrated optics waveguide device  104 , such as a waveguide device described and claimed in applicant&#39;s published PCT application WO 98/59276, the disclosure of which is hereby incorporated by reference. Device  104  is preferably embodied in a wire bond package, such as that described in FIG. 30 of applicant&#39;s published PCT application WO 98/59276. 
     FIG. 2C illustrates conventional flip-chip type mounting of an integrated optics waveguide device  100 , such as a waveguide device described and claimed in applicant&#39;s published PCT application WO 98/59276, the disclosure of which is hereby incorporated by reference. Device  100  is preferably embodied in a flip-chip package, such as that described in FIG. 31 of applicant&#39;s published PCT application WO 98/59276. 
     The mountings of FIGS. 2A and 2B are both characterized in that the waveguides of the active integrated optics waveguide device are located in a plane which is spaced from the surface of a substrate by a distance of at least a few hundred microns. This may be contrasted from the mounting of FIG. 2C, wherein the waveguides of the active integrated optics waveguide device are located in a plane which is spaced from the surface of a substrate by a distance of less than one hundred microns. 
     Reference is now made to FIGS. 3A-3F, which are simplified pictorial illustrations of a method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with a preferred embodiment of the present invention. The illustrations of FIGS. 3A-3F show a mounting of the type illustrated in FIGS. 2A &amp; 2B. 
     FIG. 3A shows a substrate  200  onto which is mounted an active integrated optics waveguide device  202  as well as various other integrated circuits  204 . As seen in FIG. 3B, an optical fiber module  206 , preferably of the type described hereinabove with reference to FIGS. 1A-1I, is brought into proximity with substrate  200  and active integrated optics waveguide device  202 , as by a vacuum engagement assembly  208 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 3C, the optical fiber module  206  is precisely positioned with respect to the active integrated optics waveguide device  202  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers in module  206  and the waveguides in device  202 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     FIG. 3D illustrates precise mounting of the optical fiber module  206  with respect to the active integrated optics waveguide device  202  on substrate  200 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the fiber optic module  206  relative to substrate  200  such that the mode of each optical fiber  209  in module  206  matches the mode of at least one corresponding waveguide of waveguide device  202  with relatively low light loss. 
     The fiber optic module  206  is mounted in a desired relative position on the substrate  200  independently of the positioner by employing side mounting blocks  210  to fix the module  206  in position on substrate  200  upon precise mutual alignment of the module  206  and the waveguide device  202 . 
     Preferably side mounting blocks  210  are carefully positioned alongside module  206  and are bonded thereto and to substrate  200 , preferably using a thin layer of UV curable adhesive  211  which does not involve significant shrinkage during curing, as by use of a UV light source  220  as shown in FIG. 3E, so that the relative position shown in FIG. 3D is preserved, as seen in FIG.  3 F. It is appreciated that in order to affix the mounting blocks  210  to the substrate  200 , a coating of the adhesive  211  is applied to the appropriate side surfaces and lower surfaces of the mounting blocks  210 . 
     The use of side mounting blocks  210  enables accurate fixation with six degrees of freedom by virtue of the use of the thin layer of adhesive  211 , which does not involve significant shrinkage during curing, along two mutually orthogonal planes. 
     Reference is now made to FIGS. 4A-4F, which are simplified pictorial illustrations of a method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with another preferred embodiment of the present invention corresponding to the embodiment of FIG.  2 C. 
     As noted above, in the mounting arrangement of FIG. 2C, the waveguides of the active integrated optics waveguide device are located in a plane which is spaced from the surface of a substrate by a distance of less than one hundred microns. In order to accommodate this very small spacing a hole or a recess is formed in the substrate to receive the optical fiber module. 
     FIG. 4A shows a substrate  300  onto which is mounted an active integrated optics waveguide device  302  as well as various other integrated circuits  304 . A hole or recess  305  is preferably formed in substrate  300  as shown. As seen in FIG. 4B, an optical fiber module  306 , preferably of the type described hereinabove with reference to FIGS. 1A-1I, is brought into proximity with substrate  300  and active integrated optics waveguide device  302 , as by a vacuum engagement assembly  308 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 4C, the optical fiber module  306  is precisely positioned with respect to the active integrated optics waveguide device  302  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers in module  306  and the waveguides in device  302 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     FIG. 4D illustrates precise mounting of the optical fiber module  306  with respect to the active integrated optics waveguide device  302  on substrate  300  partially overlapping hole  305 , such that the cylindrical lens, such as lens  40  (FIG. 1H) and the ends of the optical fibers, such as fibers  20  (FIG. 1D) lie partially below the top surface of substrate  300 . This construction ensures that the images of the centers of the ends of fibers  20  lie in the same plane as the centers of the waveguides of waveguide device  302 .This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the fiber optic module  306  relative to substrate  300  such that the mode of each optical fiber  20  in module  306  matches the mode of at least one corresponding waveguide of waveguide device  302  with relatively low light loss. 
     The fiber optic module  306  is mounted in a desired relative position on the substrate  302  independently of the positioner by employing side mounting blocks  310  to fix the module  306  in position on substrate  300  upon precise mutual alignment of the module  306  and the waveguide device  302 . 
     Preferably side mounting blocks  310  are carefully positioned alongside module  306  and are bonded thereto and to substrate  300 , preferably using a thin layer of UV curable adhesive  311  which does not involve significant shrinkage during curing, as by use of a UV light source  320  as shown in FIG. 4E, so that the relative position shown in FIG. 4D is preserved, as seen in FIG.  4 F. 
     The use of side mounting blocks  310  enables accurate fixation with six degrees of freedom by virtue of the use of the thin layer of adhesive  311 , which does not involve significant shrinkage during curing, along two mutually orthogonal planes. 
     Reference is now made to FIGS. 5A-5F, which are simplified pictorial illustrations yet another method for producing an optical device using an optical fiber module and an integrated optics waveguide assembly in accordance with yet another preferred embodiment of the present invention corresponding to the embodiment of FIG.  2 C. 
     FIG. 5A shows a substrate  400  onto which is mounted an active integrated optics waveguide device  402  as well as various other integrated circuits  404 . A hole or recess  405  is preferably formed in substrate  400  as shown. 
     In this embodiment a multiplicity of optical fibers  406  are mounted in V-grooves  407  formed in substrate  400 , such that the centers of the ends of fibers  406  all lie in the same plane as that of the centers of the waveguides of waveguide device  402 . It is appreciated that this type of structure may be adapted for use with the embodiment of FIGS. 2A and 2B by providing a raised platform portion of substrate  400  underlying V-grooves  407 . In such an arrangement, the centers of the ends of fibers  406  would all lie in the same plane as that of the centers of the waveguides of waveguide device  100  (FIG. 2A) or  104  (FIG.  2 B). 
     As seen in FIG. 5B, a lens module  408 , preferably comprising a lens  409  fixedly mounted onto a mounting substrate  410 , is brought into proximity with substrate  400  and active integrated optics waveguide device  402 , as by a vacuum engagement assembly  411 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 5C, the lens module  408  is precisely positioned with respect to the active integrated optics waveguide device  402  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers  406  and the waveguides in device  402 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     FIG. 5D illustrates precise mounting of the lens module  408  with respect to the active integrated optics waveguide device  402  on substrate  400  partially overlapping hole  405 , such that the lens  409  lies partially below the top surface of substrate  400 . This construction ensures that the images of the centers of the ends of fibers  406  lie in the same plane as the centers of the waveguides of waveguide device  402 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the lens module  408  relative to substrate  400  such that the mode of each optical fiber  406  matches the mode of at least one corresponding waveguide of waveguide device  402  with relatively low light loss. 
     The lens module  408  is mounted in a desired relative position on the substrate  400  independently of the positioner by employing side mounting blocks  412  to fix the module  408  in position on substrate  400  upon precise mutual alignment of the module  408  and the waveguide device  402 . 
     Preferably side mounting blocks  412  are carefully positioned alongside module  408  and are bonded thereto and to substrate  400 , preferably using a thin layer of UV curable adhesive  413  which does not involve significant shrinkage during curing, as by use of a UV light source  420  as shown in FIG. 5E, so that the relative position shown in FIG. 5D is preserved, as seen in FIG.  5 F. 
     The use of side mounting blocks  412  enables accurate fixation with six degrees of freedom by virtue of the use of the thin layer of adhesive  413 , which does not involve significant shrinkage during curing, along two mutually orthogonal planes. 
     Reference is now made to FIGS. 6A-6E, which are simplified pictorial illustrations of a method for associating output optics with the optical device of FIG. 3F in accordance with a preferred embodiment of the present invention; 
     FIG. 6A shows a chassis  500  onto which is mounted an optical device  501 , preferably the optical device described hereinabove and shown in FIG.  3 F. For the sake of conciseness and clarity, the reference numerals appearing in FIG. 3F are employed also in FIG. 6A as appropriate. Also mounted on chassis  500  is an optical fiber bundle  502  and a lens  504  arranged such that the center of the lens  504  lies in the same plane as the centers of the ends of the fibers in fiber bundle  502  within conventional mechanical tolerances, such as 10-50 microns. 
     As seen in FIG. 6A, a lens module  508 , preferably comprising a lens  509  fixedly mounted onto a mounting substrate  510 , is brought into proximity with substrate  200  of device  501  and active integrated optics waveguide device  202  of device  501 , as by a vacuum engagement assembly  511 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 6B, the lens module  508  is precisely positioned with respect to the active integrated optics waveguide device  202  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers of fiber bundle  502  and the waveguides in device  202 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     FIG. 6C illustrates precise mounting of the lens module  508  with respect to the active integrated optics waveguide device  202  of device  501 . This construction ensures that the images of the centers of the ends of fibers of fiber bundle  502  lie in the same plane as the centers of the waveguides of waveguide device  202 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the lens module  508  relative to substrate  200  such that the mode of each optical fiber in bundle  502  matches the mode of at least one corresponding waveguide of waveguide device  202  with relatively low light loss. 
     The lens module  508  is mounted in a desired relative position on the substrate  200  independently of the positioner by employing side mounting blocks  512  to fix the module  508  in position on substrate  200  upon precise mutual alignment of the module  508  and the waveguide device  202 . 
     Preferably side mounting blocks  512  are carefully positioned alongside module  508  and are bonded thereto and to substrate  200 , preferably using a thin layer of UV curable adhesive  513  which does not involve significant shrinkage during curing, as by use of a UV light source  520  as shown in FIG. 6D, so that the relative position shown in FIG. 6C is preserved, as seen in FIG.  6 E. 
     The use of side mounting blocks  512  enables accurate fixation with six degrees of freedom by virtue of the use of the thin layer of adhesive  513 , which does not involve significant shrinkage during curing, along two mutually orthogonal planes. 
     Reference is now made to FIGS. 7A-7D, which are simplified pictorial illustrations of a method for constructing an integrated optics optical fiber switch using a plurality of base substrates bearing integrated optics waveguide assemblies and optical fiber modules as shown in FIG.  3 F. 
     The switch is constructed on the basis of the apparatus shown in FIG.  6 E. For the sake of conciseness and clarity, the reference numerals appearing in FIG. 6E are also employed, as appropriate in FIGS. 7A-7D. As seen in FIG. 7A an optical device  601 , preferably identical to optical device  501  (FIG.  6 E), as shown in FIG. 3F, is stacked over optical device  501  and spaced therefrom by mounting spacers  602 . For the sake of conciseness and clarity, the reference numerals appearing in FIG. 3F are also employed, as appropriate in FIGS. 7A-7D. Spacers  602  may be mounted either on device  501  as shown or alternatively on device  601  or on chassis  500 . 
     The alignment between devices  501  and  601  may be within conventional mechanical tolerances, such as  10  microns. The most important aspect of the alignment between devices  501  and  601  is the parallelism of the planes of the respective substrates  200  of devices  501  and  601  about the axes of the waveguides of respective optical devices  202 . 
     As seen in FIG. 7B, a lens module  608 , preferably comprising a lens  609  fixedly mounted onto a mounting substrate  610 , is brought into proximity with substrate  200  of device  601  and active integrated optics waveguide device  202  of device  601 , as by a vacuum engagement assembly  611 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 7C, the lens module  608  is precisely positioned with respect to the active integrated optics waveguide device  202  of device  601  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers of fiber bundle  502  and the waveguides in device  202  of device  601 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     Precise mounting of the lens module  608  with respect to the active integrated optics waveguide device  202  of device  601  as described hereinabove with respect to device  501  ensures that the images of the centers of the ends of fibers of fiber bundle  502  lie in the same plane as the centers of the waveguides of waveguide device  202  of device  601 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the lens module  608  relative to substrate  200  of device  601  such that the mode of each optical fiber in bundle  502  matches the mode of at least one corresponding waveguide of waveguide device  202  of device  601  with relatively low light loss. 
     As seen in FIG. 7D, the lens module  608  is mounted in a desired relative position on the substrate  200  of device  601  independently of the positioner by employing side mounting blocks  612  to fix the module  608  in position on substrate  200  of device  601  upon precise mutual alignment of the module  608  and the waveguide device  202  of device  601 . 
     Preferably side mounting blocks  612  are carefully positioned alongside module  608  and are bonded thereto and to substrate  200  of device  601 , preferably using a thin layer of UV curable adhesive  613  which does not involve significant shrinkage during curing, as by use of a UV light source (not shown). 
     Reference is now made to FIGS. 8A-8D, which are simplified pictorial illustrations of a method for associating output optics with the optical device of FIG. 4F in accordance with a preferred embodiment of the present invention; 
     FIG. 8A shows a chassis  700  onto which is mounted an optical device  701 , preferably the optical device described hereinabove and shown in FIG.  4 F. For the sake of conciseness and clarity, the reference numerals appearing in FIG. 4F are employed also in FIG. 8A as appropriate. Also mounted on chassis  700  is an optical fiber bundle  702  and a lens  704  arranged such that the center of the lens  704  lies in the same plane as the centers of the ends of the fibers in fiber bundle  702  within conventional mechanical tolerances, such as 10-50 microns. 
     As seen in FIG. 8A, a lens module  708 , preferably comprising a lens  709  fixedly mounted onto a mounting substrate  710 , is brought into proximity with substrate  300  of device  701  and active integrated optics waveguide device  302  of device  701 , as by a vacuum engagement assembly  711 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     As seen in FIG. 8B, the lens module  708  is precisely positioned with respect to the active integrated optics waveguide device  302  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers of fiber bundle  702  and the waveguides in device  302 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     FIG. 8C illustrates precise mounting of the lens module  708  with respect to the active integrated optics waveguide device  302  of device  701 . This construction ensures that the images of the centers of the ends of fibers of fiber bundle  702  lie in the same plane as the centers of the waveguides of waveguide device  302 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the lens module  708  relative to substrate  300  such that the mode of each optical fiber in bundle  702  matches the mode of at least one corresponding waveguide of waveguide device  302  with relatively low light loss. 
     The lens module  708  is mounted in a desired relative position on the substrate  300  independently of the positioner by employing side mounting blocks  712  to fix the module  708  in position on substrate  300  upon precise mutual alignment of the module  708  and the waveguide device  302 . 
     Preferably side mounting blocks  712  are carefully positioned alongside module  708  and are bonded thereto and to substrate  300 , preferably using a thin layer of UV curable adhesive  713  which does not involve significant shrinkage during curing, as by use of a UV light source  720  as shown in FIG. 8C, so that the relative position shown in FIG. 8C is preserved, as seen in FIG.  8 D. 
     The use of side mounting blocks  712  enables accurate fixation with six degrees of freedom by virtue of the use of the thin layer of adhesive  713 , which does not involve significant shrinkage during curing, along two mutually orthogonal planes. 
     Reference is now made to FIGS. 9A-9D, which are simplified pictorial illustrations of a method for constructing an integrated optics optical fiber switch using a plurality of base substrates bearing integrated optics waveguide assemblies and optical fiber modules as shown in FIG.  4 F. 
     The switch is constructed on the basis of the apparatus shown in FIG.  8 D. For the sake of conciseness and clarity, the reference numerals appearing in FIG. 8D are also employed, as appropriate in FIGS. 9A-9D. As seen in FIG. 9A an optical device  801 , preferably identical to optical device  701  (FIG.  8 D), as shown in FIG. 4F, is stacked over optical device  701  and spaced therefrom by mounting spacers  802 . For the sake of conciseness and clarity, the reference numerals appearing in FIG. 4F are also employed, as appropriate in FIGS. 9A-9D. Spacers  802  may be may mounted either on device  701  as shown or alternatively on device  801  or on chassis  700 . 
     The alignment between devices  701  and  801  may be within conventional mechanical tolerances, such as 10 microns. The most important aspect of the alignment between devices  701  and  801  is the parallelism of the planes of the respective substrates  300  of devices  701  and  801  about the axes of the waveguides of respective optical devices  302  (FIG.  9 B). 
     As seen in FIG. 9C, a lens module  808 , preferably comprising a lens  809  fixedly mounted onto a mounting substrate  810 , is brought into proximity with substrate  300  of device  801  and active integrated optics waveguide device  302  of device  801 , as by a vacuum engagement assembly  811 , connected to a suitable positioner (not shown), such as Melles Griot Nanoblock. 
     Also seen in FIG. 9C, the lens module  808  is precisely positioned with respect to the active integrated optics waveguide device  302  of device  801  with six degrees of freedom so as to achieve a high degree of accuracy in order to realize optimal optical coupling efficiency between the fibers of fiber bundle  702  and the waveguides in device  302  of device  801 . This degree of accuracy is greater than that required in the previously described alignment steps illustrated in FIGS. 1A-1I and preferably reaches one tenth of a micron. 
     Precise mounting of the lens module  808  with respect to the active integrated optics waveguide device  302  of device  801  as described hereinabove with respect to device  701  ensures that the images of the centers of the ends of fibers of fiber bundle  702  lie in the same plane as the centers of the waveguides of waveguide device  302  of device  801 . This precise mounting is preferably achieved by using the positioner (not shown) to manipulate the lens module  808  relative to substrate  300  of device  801  such that the mode of each optical fiber in bundle  702  matches the mode of at least one corresponding waveguide of waveguide device  302  of device  801  with relatively low light loss. 
     As seen in FIG. 9D, the lens module  808  is mounted in a desired relative position on the substrate  300  of device  801  independently of the positioner by employing side mounting blocks  812  to fix the module  808  in position on substrate  300  of device  801  upon precise mutual alignment of the module  808  and the waveguide device  302  of device  801 . 
     Preferably side mounting blocks  812  are carefully positioned alongside module  808  and are bonded thereto and to substrate  300  of device  801 , preferably using a thin layer of UV curable adhesive  813  which does not involve significant shrinkage during curing, as by use of a UV light source  820 . 
     It will be appreciated by persons skilled in the art that the present invention is not limited by the claims which follow, rather the scope of the invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications thereof which would occur to a person of ordinary skill in the art upon reading the foregoing description and which are not in the prior art.