Abstract:
A substrate is provided herein for supporting at least one optical fiber, and preferably a plurality of parallel optical fibers. The substrate includes a base substrate of a suitable material a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof at least one longitudinally-extending groove, and preferably a plurality of parallel grooves, along the longitudinally-extending axis, and abutting the strain-relief area 10 and a first and optionally also a second transversely-extending trench across the substrate. Two such substrates may provide a bottom plate and a top plate, which are superposed to provide a precursor sandwich which supports one or more optical fibers. The precursor sandwich comprises the top plate which is superposed over the bottom plate, with one or more optical fibers therebetween in the strain-relief area, and with one or more bare exposed optical fibers in the longitudinally-extending groove or grooves. Further, a minor section of the top plate and the bottom plate of the precursor sandwich have been glued together. This precursor sandwich can be further processed to provide useful half-sandwiches and full sandwiches.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to methods for preparing multiple optical fibers, also referred to as fiber arrays, for interconnection to other optical fibers, or to waveguides fabricated on a substrate constructed from silica, polymer, silicon, or other light guiding materials. The invention also relates to fiber connectors in general, and in particular to devices for interconnecting fibers and planar waveguides.  
           [0003]    2 Description of the Prior Art  
           [0004]    U.S. Pat. No. 5,787,214 patented Jul. 28, 1998 by Harpin et al provided a connection between an integrated optical waveguide and an optical fiber. That connection has a layer of silicon in which a rib waveguide is formed separated from a substrate by a layer of silicon dioxide. A V-groove is formed in the substrate for receiving an optical fiber, and the V-groove is arranged to align the optical fiber at a predetermined angle with respect to the waveguide. The rib waveguide and the underlying layer of silicon dioxide are formed to overhang the end of the V-groove so that the end of the waveguide is in close proximity with the end of an optical fiber positioned in the V-groove.  
           [0005]    U.S. Pat. No. 6,112,002 patented Aug. 29, 2001 by Tabachi provided a semiconductor laser and an optical waveguide of an optical coupler, formed on a substrate. These are optically coupled with each other by aligning their positions horizontally by using a plurality of laser elements and cores for the laser and the waveguide respectively and arranging them in an array respectively so that a difference between their pitches is less than double of tolerance tolerated for optically coupling with each other. The waveguide has a composite core composed of a main core, a sub core surrounding the main core and having a refractive index lower than that of the main core; and a cladding layer surrounding the sub core and having a refractive index lower than that of the sub core.  
           [0006]    U.S. Pat. No. 6,185,348 patented Feb. 2001 provided an apparatus and method for assembling a multifiber interconnection circuit where the circuit includes at least one elongated member disposed between a first cover member and a second cover member. The apparatus included a template, a receiving member, and a transfer member. The template had a first end and a second end and a means for routing an elongated member, such as an optical fiber, from the first end of the template to the second end of the template. The receiving member was arranged and configured to receive the optical fiber engaged by the template. The transfer member was configured to support the receiving member for reception of the optical fiber.  
           [0007]    Canadian Patent Application No. 2,258,103 shows how to make an optical connector by precisely embedding optical fibers in a substrate using lithography, molding, laser, chemical or mechanical micromachining, then using a covering adhesive or the like to keep the fibers in place. The ends of the substrate are cut off forming optical connectors with precisely aligned fiber faces that may be polished. This prior art method produces an array of fibers which, however are not angled, not exposed, and are intended for re-connection to the same substrate from which they were cut.  
         SUMMARY OF THE INVENTION  
       Aims of the Invention  
         [0008]    This invention aims to provide an efficient method for preparing multiple optical fibers, also referred to as fiber arrays, for interconnection to optical fibers, or to waveguides fabricated on a substrate constructed from silica, polymer, silicon, or other suitable light-guiding materials.  
         Statement of Invention  
         [0009]    The present invention provides a method for preparing a substrate for supporting at least one optical fiber. The method includes providing a base substrate of a suitable material. A longitudinally-extending, strain-relief area is formed at one end thereof along a longitudinal axis thereof At least one longitudinally-extending groove is formed along the longitudinally-extending axis, that at least one longitudinally-extending groove abutting the strain-relief area. At least a first transversely-extending trench is formed across the substrate, prior to positioning the at least one optical fiber thereon.  
           [0010]    The present invention also provides a method for preparing a substrate for supporting a plurality of optical fibers. That method includes a base substrate of a suitable material. A longitudinally-extending, strain-relief area is provided one end thereof along a longitudinal axis thereof A plurality of parallel, longitudinally-extending grooves is provided along the longitudinally-extending axis, those longitudinally-extending grooves abutting the strain-relief area. At least a first transversely-extending trench is formed across the substrate, prior to positioning the plurality of optical fibers thereon.  
           [0011]    The present invention also provides a method for preparing an element which supports at least one optical fiber. That method include the first step of providing a bottom plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing at least one longitudinally-extending groove along the longitudinally-extending axis, that at least one longitudinally-extending groove abutting the strain-relief area, and providing at least a first transversely-extending trench across said substrate.  
           [0012]    The next step involves providing a top plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing at least one longitudinally-extending groove along the longitudinally-extending axis, that at least one longitudinally-extending groove abutting the strain-relief area, and providing at least a first transversely-extending trench across the substrate.  
           [0013]    The next step involves disposing at least one optical fiber within the strain-relief area of either the bottom plate or the top plate and disposing at least one bare optical fiber within the longitudinally-extending groove of either the bottom plate or the top plate.  
           [0014]    The final step involves preparing a precursor sandwich by superposing the top plate over the bottom plate with the at least one optical fiber therebetween in the strain-relief areas and with the at least one bare exposed optical fiber in the grooves and with a minor section of the top plate and the bottom plate of the precursor sandwich being glued together.  
           [0015]    The present invention also provides a method for preparing an element which supports a plurality of optical fibers. That method includes the first step of providing a bottom plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinally axis thereof, providing a plurality of parallel, longitudinally-extending grooves along the longitudinally-extending axis, that plurality of parallel longitudinally-extending grooves abutting the strain-relief area, and providing at least a first transversely-extending trench across the substrate.  
           [0016]    The next step involves providing a top plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing a plurality of parallel longitudinally-extending grooves along the longitudinally-extending axis the plurality of parallel longitudinally-extending grooves abutting the strain-relief area, and providing at least a first transversely-extending trench across the substrate.  
           [0017]    The next step involves disposing an array of optical fibers within the strain-relief area of either the bottom plate or the top plate, and disposing a plurality of parallel bare optical fibers within the parallel longitudinally-extending grooves of either the bottom plate or the top plate.  
           [0018]    The final step involves preparing a precursor sandwich by superposing the top plate over the bottom plate with the array of optical fibers therebetween in the strain-relief areas and with the plurality of parallel bare exposed optical fibers in the grooves, and with a minor section of the top plate and the bottom plate and the precursor sandwich being glued together.  
           [0019]    The present invention also provides a method for preparing an element which supports at least one optical fiber. That method includes the first step of providing a bottom plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, providing a first transversely-extending trench across the substrate, and providing a second trench extending transversely across the substrate at a location remote from the first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0020]    The next step includes providing a top plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinally-extending axis thereof, providing at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, providing a first transversely-extending trench across the substrate, and providing a second trench extending transversely across the substrate at a location remote from the first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0021]    The next step includes disposing at least one optical fiber within the strain-relief area of either the bottom plate or the top plate and disposing at least one bare optical fiber within the longitudinally-extending groove of either the bottom plate or the top plate. The preparing a precursor sandwich by superposing the top plate over the bottom plate with the at least one optical fiber therebetween in the strain-relief areas and with the at least one bare exposed optical fiber in the grooves, and with a minor section of the top plate and the bottom plate of the precursor sandwich being glued together.  
           [0022]    The present invention also provides a method for preparing an element which supports a plurality of optical fibers. The method includes the first step of providing a bottom plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing a plurality of parallel longitudinally-extending grooves along the longitudinally-extending axis, the plurality of parallel longitudinally-extending grooves abutting the strain-relief area, providing a first transversely-extending trench across the substrate, and providing a second trench extending transversely across the substrate at a location remote from the first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0023]    The next step involves, providing a top plate in the form of a base substrate of a suitable material, providing a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, providing a plurality of parallel longitudinally-extending grooves along said longitudinally-extending axis, the plurality of parallel longitudinally-extending grooves abutting said strain-relief area, providing a first transversely-extending trench across said substrate, and providing a second trench extending transversely across the substrate at a location remote from said first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0024]    The next step includes disposing an array of optical fibers within the strain-relief area of either the bottom plate or the top plate and disposing a plurality of bare optical fibers within the plurality of parallel, longitudinally-extending grooves of either the bottom plate or the top plate.  
           [0025]    The final step includes preparing a precursor sandwich by superposing the top plate over the bottom plate with the array of optical fibers therebetween in the strain-relief areas and with the plurality of parallel bare exposed optical fibers in the plurality of parallel grooves, and with a minor section of the top plate and the bottom plate of the precursor sandwich being glued together.  
           [0026]    The present invention also provides a method for the production of a waveguide. The method includes the steps of providing a waveguide substrate, the waveguide substrate having two opposed lateral ends, each lateral end including a plurality of parallel longitudinal grooves therein and a central region abutting the lateral ends, the central region including a plurality of optical-fiber-coupling structures which abut the plurality of parallel longitudinal grooves. Two half-sandwiches as described hereabove are provided.  
           [0027]    An associated half-sandwich is secured to an associated lateral end of the waveguide substrate, with the exposed optical fibers within the plurality of parallel grooves of the waveguide substrate, and also in contact with the optical fiber coupling structures.  
           [0028]    The present invention also provides a method for the production of a waveguide. The method includes providing a waveguide substrate, the waveguide substrate having two opposed lateral ends, each lateral end including a plurality of parallel longitudinal grooves therein, and a central region abutting the lateral ends, the central region including a plurality of optical-fiber-coupling structures which abut the plurality of parallel longitudinal grooves. Two full sandwiches as described hereabove are provided.  
           [0029]    An associated full sandwich is secured to an associated lateral end of the waveguide substrate, with the exposed optical fibers within the plurality of parallel grooves of the waveguide substrate, and also in contact with the optical fiber coupling structures.  
           [0030]    The present invention also provides a substrate for supporting at least one optical fiber. The substrate includes a base substrate of a suitable material. A longitudinally-extending strain-relief area is provided at one end thereof along a longitudinal axis thereof At least one longitudinally-extending groove is provided along said longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area. At least a first transversely-extending trench across the substrate.  
           [0031]    The present invention also provides a substrate for supporting a plurality of optical fibers. The substrate includes a base substrate of a suitable material. A longitudinally-extending strain-relief area is provided at one end thereof along a longitudinal axis thereof. A plurality of parallel, longitudinally-extending grooves is provided along the longitudinally-extending axis, the plurality of parallel, longitudinally-extending grooves abutting the strain-relief area. At least a first transversely-extending trench is provided across said substrate.  
           [0032]    The present invention also provides a precursor sandwich which supports at least one optical fiber. The precursor sandwich includes a bottom plate in the form of a base substrate of a suitable material, a longitudinally extending strain-relief area at one end thereof along a longitudinal axis thereof, at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, and at least a first transversely-extending trench across the substrate.  
           [0033]    The precursor sandwich also includes a top plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, and at least a first transversely-extending trench across the substrate.  
           [0034]    The precursor sandwich also includes at least one optical fiber within the strain-relief area of either the bottom plate or the top plate, and at least one bare exposed optical fiber within the at least one longitudinally-extending groove in either the bottom plate or the top plate.  
           [0035]    In this way, the precursor sandwich comprises the top plate which is superposed over the bottom plate, with the at least one optical fiber therebetween in the strain-relief area, and with the at least one bare exposed optical fiber in the at least one longitudinally-extending groove, and further in which a minor section of the top plate and the bottom plate of the precursor sandwich have been glued together.  
           [0036]    The present invention also provides a precursor sandwich supports a plurality of parallel optical fibers. The precursor sandwich includes a bottom plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, a plurality of parallel, longitudinally-extending grooves along the longitudinally-extending axis, the plurality of parallel, longitudinally-extending grooves abutting the strain-relief area, and at least a first transversely-extending trench across the substrate.  
           [0037]    The precursor sandwich also includes a top plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, a plurality of parallel, longitudinally-extending grooves along said longitudinally-extending axis, the plurality of parallel, longitudinally-extending grooves abutting said strain-relief area, and at least a first transversely-extending trench across said substrate.  
           [0038]    The precursor sandwich also includes an array of optical fibers within the strain-relief area of either the bottom plate or the top plate, and a plurality of parallel, bare exposed optical fibers within the plurality of parallel, longitudinally-extending grooves in either the bottom plate or the top plate.  
           [0039]    In this way, the precursor sandwich comprises the top plate which is superposed over the bottom plate, with the array of optical fibers therebetween in the strain-relief area, and with the plurality of parallel, exposed optical fibers in the plurality of parallel, longitudinally-extending grooves, and further in which a minor section of the top plate and the bottom plate of the precursor sandwich have been glued together.  
           [0040]    The present invention also provides a precursor sandwich supports at least one optical fiber. The precursor sandwich includes a bottom plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, a first transversely-extending trench across the substrate, and a second transversely-extending trench across the substrate and adjacent an end of the substrate which is remote from the first trench.  
           [0041]    The precursor sandwich also includes a top plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, at least one longitudinally-extending groove along the longitudinally-extending axis, the at least one longitudinally-extending groove abutting the strain-relief area, a first transversely-extending trench across the substrate and a second transversely-extending trench across the substrate and adjacent an end of the substrate which is remote from the first trench.  
           [0042]    The precursor sandwich also includes at least one optical fiber within the strain-relief area of either the bottom plate or the top plate, and at least one bare exposed optical fiber within the at least one longitudinally-extending groove in either the bottom plate or the top plate.  
           [0043]    In this way, the precursor sandwich comprises the top plate which is superposed over the bottom plate, with the at least one optical fiber therebetween in the strain-relief area, and with the at least one bare exposed optical fiber in the at least one longitudinally-extending groove, and further in which a minor section of the top plate and the bottom plate of the precursor sandwich has been glued together.  
           [0044]    The present invention also provides a precursor sandwich which supports a plurality of parallel optical fibers. The precursor sandwich includes a bottom plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof a plurality of parallel, longitudinally-extending grooves along the longitudinally-extending axis, the plurality of parallel, longitudinally-extending grooves abutting the strain-relief area, a first transversely-extending trench across the substrate and a second transversely-extending trench across the substrate and adjacent an end of the substrate which is remote from the first trench.  
           [0045]    The precursor sandwich also includes a top plate in the form of a base substrate of a suitable material, a longitudinally-extending strain-relief area at one end thereof along a longitudinal axis thereof, a plurality of parallel, longitudinally-extending grooves along the longitudinally-extending axis, the plurality of parallel, longitudinally-extending groove abutting the strain-relief area, a first transversely-extending trench across the substrate, and a second transversely-extending trench across the substrate and adjacent an end of the substrate which is remote from the first trench.  
           [0046]    The precursor sandwich also includes an array of optical fibers within the strain-relief area of either the bottom plate or the top plate, and a plurality of parallel, bare exposed optical fibers within the plurality of parallel, longitudinally-extending grooves in either the bottom plate or the top plate.  
           [0047]    In this way, the precursor sandwich comprises the top plate which is superposed over the bottom plate, with the array of optical fibers therebetween in the strain-relief area, and with the plurality of parallel, exposed optical fibers in the plurality of parallel, longitudinally-extending grooves, further in which a minor section of the top plate and the bottom plate of the precursor sandwich have been glued together.  
           [0048]    The present invention also provides a half-sandwich comprising the precursor sandwich as described above, in which the bottom plate has been broken away along the first trench thereof, in which a major unglued portion of the bottom plate has been removed. Thus the half-sandwich includes the optical fiber array and at least one bare exposed optical fiber which is within the at least one groove, or the plurality of parallel exposed optical fibers are within the plurality of parallel grooves, the at least one bare exposed optical fiber, or the plurality of parallel exposed optical fibers depending from a face of the top plate and along the longitudinal axis of the half-sandwich.  
           [0049]    The present invention also provides a full sandwich comprising the half-sandwich as described above, in which the top plate has been broken away along the first trench thereof, in which a major unglued portion of the top plate has been removed.  
           [0050]    Thus, the full sandwich includes the optical fiber array and at least one bare exposed optical fiber which is cantelevered from the remaining minor portion of the top plate and the bottom plate, or the plurality of parallel exposed optical fibers which are cantelevered from the remaining minor portion of the top plate and the bottom plate and along the longitudinal axis of the fill sandwich.  
           [0051]    The present invention also provides a waveguide comprising a waveguide substrate having two opposed lateral ends, each lateral end including a plurality of parallel longitudinal grooves therein, and a central region abutting both the lateral ends, the central region including a plurality of parallel optical-fiber-coupling structures which abut the plurality of parallel grooves.  
           [0052]    The waveguide also includes associated half-sandwich as described above which is secured to an associated lateral end of the waveguide substrate, with the plurality of parallel exposed optical fibers within the plurality of parallel grooves in the lateral ends of the waveguide substrate, and also in contact with the plurality of parallel optical-fiber-coupling structures.  
           [0053]    The present invention also provides a waveguide comprising a waveguide substrate having two opposed lateral ends, each lateral end including a plurality of parallel longitudinal grooves therein, and a central region abutting both lateral ends, the central region including a plurality of parallel optical-fiber-coupling structures which abut the plurality of parallel grooves.  
           [0054]    The waveguide also includes an associated full sandwich as described above which is secured to an associated lateral end of the waveguide substrate, with the plurality of parallel exposed optical fibers within the plurality of parallel grooves in the lateral ends of the waveguide substrate, and also in contact with the plurality of parallel optical-fiber-coupling structures.  
         Other Features of the Invention  
         [0055]    A first feature of the method of this invention is where the strain-relief area extends longitudinally on both lateral sides of the first trench.  
           [0056]    A second feature of the methods of this invention is where the strain-relief area extends longitudinally from said first trench only to said one edge thereof.  
           [0057]    A third feature of the method of this invention is where the strain-relief area extends longitudinally from said one edge thereof to stop short of said strain-relief area.  
           [0058]    A fourth feature of the methods of this invention is one which includes providing a second trench extending transversely across the substrate at a location remote from the first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0059]    A fifth feature of the methods of this invention is where the at least one optical fiber, or the array of optical fibers, and the at least one bare exposed optical fiber or the plurality of parallel bare exposed optical fibers is disposed at an angle beta to the central longitudinal axis of the precursor sandwich.  
           [0060]    A sixth feature of the methods of this invention is one which include the step of breaking the bottom plate of the precursor sandwich along the first trench, and removing a major unglued section of the bottom plate, thereby providing a half-sandwich including the at least one bare exposed optical fiber or the plurality of parallel bare exposed optical fibers, both within the at least one groove or within the plurality of parallel grooves and depending from a face of the top plate.  
           [0061]    A seventh feature of the methods of this invention is one which includes the additional steps of cutting the precursor sandwich adjacent an edge which is remote from the first trench, and breaking away a portion of the top plate thereby exposing an end of the at least one bare exposed optical fiber or the ends of the plurality of parallel bare exposed optical fibers and polishing the exposed end or ends of the optical fiber or fibers.  
           [0062]    An eight feature of the methods of this invention is one where the cut is tilted at an angle gamma to the vertical.  
           [0063]    A ninth feature of the methods of this invention is one where the cut is completely through the top plate but only partly through the lower plate.  
           [0064]    A tenth feature of the methods of this invention is where the cut is disposed at an angle delta to the longitudinal axis of said precursor sandwich.  
           [0065]    An eleventh feature of the methods of this invention is where the said bare exposed optical fiber or said plurality of parallel bare exposed optical fibers are disposed at an angle theta to the longitudinal axis of the said precursor sandwich.  
           [0066]    A twelfth feature of the methods of this invention is where the additional steps of breaking the top plate the half-sandwich along the first trench of the top plate, and removing a major unglued section of the top plate thereby providing a fall sandwich including a bare exposed cantelevered optical fiber or plurality of parallel bare exposed cantelevered optical fibers, which extend along the longitudinal axis of said full sandwich.  
           [0067]    A thirteenth feature of this invention provides a substrate in which the strain-relief area extends longitudinally on both lateral sides of the first trench.  
           [0068]    A fourteenth feature of this invention provides a substrate in which the strain-relief area extends longitudinally from the first trench only to that one end thereof.  
           [0069]    A fifteenth feature of this invention provides a substrate in which the strain-relief area extends longitudinally from said one end thereof to stop short of the first trench.  
           [0070]    A sixteenth feature of this invention provides a substrate in which includes a second transversely-extending trench across the substrate at a location remote from the first trench and adjacent an end of the substrate which is remote from the first trench.  
           [0071]    A seventeenth feature of this invention provides a precursor sandwich in which the said strain-relief area extends longitudinally on both lateral sides of the first trench.  
           [0072]    An eighteenth feature of this invention provides a precursor sandwich in which the strain-relief area extends longitudinally from the first trench only to that one end thereof.  
           [0073]    A nineteenth feature of this invention provides a precursor sandwich in which the said strain-relief area extends longitudinally from said one end thereof to stop short of said first trench.  
           [0074]    A twentieth feature of this invention provides a precursor sandwich in which the at least one optical fiber or the array of optical fibers, and the at least one bare exposed optical fiber or the plurality of parallel bare exposed optical fibers, is or are, disposed at an angle beta to the central longitudinal axis of the precursor sandwich.  
           [0075]    A twenty-first feature of this invention provides a precursor sandwich in which the precursor sandwich has been cut adjacent an end which is remote from the first trench, and in which a portion of the top plate has been broken away thereby providing an exposed end of an optical fiber or exposed ends of the optical fibers, which preferably have been polished.  
           [0076]    A twenty-second feature of this invention provides a precursor sandwich in which the cut is tilted at an angle gamma to the vertical.  
           [0077]    A twenty-hird feature of this invention provides a precursor sandwich in which the cut is in the form of a cut which has been cut completely through the top plate but only partly through the bottom plate.  
           [0078]    A twenty-fourth feature of this invention provides a precursor sandwich in which the cut is disposed at an angle delta to the longitudinal axis of the precursor sandwich.  
           [0079]    A twenty-fifth feature of this invention provides a precursor sandwich in which the bare exposed optical fiber or the plurality of parallel exposed optical fibers is, or are, disposed at an angle theta to the longitudinal axis of the precursor sandwich.  
         Generalized Description of the Invention  
         [0080]    In other words, the invention uses a first, bottom silicon substrate to hold the fibers in accurate alignment. The first substrate has parallel V-grooves into which fibers can be placed with precise alignment, a rectangular excavation (strain relief area) which is large enough to hold the fiber buffer that typically protects fiber arrays, and a trench that is used to form an epoxy dam as well as the break line for removing a part of the substrate, thus exposing a portion of the fibers. The trench in the plate serves as a stress concentrator and ensures that the plate will break at the desired location when pressure is applied to the free end of the plate.  
           [0081]    A second, top silicon plate with matching V-grooves and strain relief area is placed onto the bottom substrate forming a fiber sandwich. The top silicon plate may also have trenches for breaking away a part of the top plate and further exposing the fibers.  
           [0082]    The top and bottom plates of the sandwich are secured together with epoxy forming a single unit that is holding the fibers firmly in place for preparation. The epoxy is confined to two areas of the sandwich; one area is behind the trench at the strain relief end of the sandwich; and the other area is at the end of the sandwich opposite the strain relief area,  
           [0083]    The end of the sandwich opposite the strain relief are may now be cut off at any predetermined angle and length, and the exposed fiber ends polished if required.  
           [0084]    To expose the bottom half of the fibers, the bottom plate may be broken away at the trench. To completely expose a length of fibers, both the top and bottom plates may be broken away at the trenches.  
           [0085]    The resulting package is an accurately prepared fiber array with the ability to expose any pre-determined length of fibers. In addition, the sections of the silicon plates attached at the strain relief area serve as a handling platform for automated or manual manipulation of the fiber array. Standard manufacturing techniques such as alignment fiducials could be used to assist the manipulation process.  
           [0086]    The break-away sandwich invention disclosed herein has numerous advantages over previous inventions. It provides a reliable holding mechanism for the fibers that allows the fibers to be aligned, cut, angled and polished with high precision. It provides a simple means for exposing any reasonable length of the fibers, as well as optionally exposing only the top or bottom halves of the fibers. In addition, the invention provides a handling means that both protects the fibers, and facilitates low cost manufacturing of optical components utilizing the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0087]    The present invention will now be described in detail in conjunction with annexed drawings FIGS.  1  to  28  illustrating steps in the methods of embodiments of the invention and devices of embodiments of the invention, in which:  
         [0088]    [0088]FIG. 1 is an isometric view of a silicon substrate for the production of a package for an accurately prepared fiber array of one embodiment of this invention;  
         [0089]    [0089]FIG. 2 is an isometric view of a bottom plate comprising the silicon substrate of FIG. 1 and a fiber buffer and a fiber array of a second embodiment of this invention;  
         [0090]    [0090]FIG. 3 is an isometric view of a silicon substrate for the production of a package for an accurately prepared fiber array of a third embodiment of this invention;  
         [0091]    [0091]FIG. 4 is an isometric view of a bottom plate comprising the silicon substrate of FIG. 3 and a fiber buffer and a fiber array of a fourth embodiment of this invention;  
         [0092]    [0092]FIG. 5 is an isometric view of a silicon substrate for the production of a package for an accurately prepared fiber array of a fifth embodiment of this invention;  
         [0093]    [0093]FIG. 6 is an isometric view of a bottom plate comprising the silicon substrate of FIG. 1 and fiber buffer and a fiber array of a sixth embodiment of this invention;  
         [0094]    [0094]FIG. 7 is an isometric view of a silicon substrate upper plate as shown in FIG. 1 and a bottom silicon plate as shown in FIG. 2 in side-by side relationship before begin mated into a fiber sandwich;  
         [0095]    [0095]FIG. 8 is an isometric intermediate view of the silicon substrate upper plate as shown in FIG. 7 being mated with the bottom silicon plate as shown in FIG. 7 in the formation into a fiber sandwich;  
         [0096]    [0096]FIG. 9 is an isometric view of the fiber sandwich according to another embodiment of this invention which has been formed as shown in FIG. 8  
         [0097]    [0097]FIG. 10 is an isometric view of the fiber sandwich according to another embodiment of this invention which has been formed as shown in FIG. 8, but where the end face has been completely cut through;  
         [0098]    [0098]FIG. 11 is a side elevational view of the fiber sandwich shown in FIG. 10;  
         [0099]    [0099]FIG. 12 is an isometric view of a fiber half sandwich shown in FIG. 10, but in another embodiment after the bottom silicon plate has been broken away;  
         [0100]    [0100]FIG. 13 is a side elevational view of the fiber half sandwich shown in FIG. 12, but in another embodiment also showing the trench;  
         [0101]    [0101]FIG. 14 is an isometric view, looking from the bottom, of a fiber half sandwich according to the embodiment of the invention shown in FIG. 12;  
         [0102]    [0102]FIG. 15 is an isometric view of a fiber full sandwich according to another embodiment of this invention but also showing the fibers being fully exposed after breaking away of the silicon substrate upper plate and the bottom silicon plate;  
         [0103]    [0103]FIG. 16 is an isometric view of a fiber full sandwich of FIG. 15, but in another embodiment also showing and extended fiber buffer;  
         [0104]    [0104]FIG. 17 is an isometric view of an intermediate stage in the production of an improved waveguide device according to another embodiment of this invention including the fiber half sandwich of FIG. 12;  
         [0105]    [0105]FIG. 18 is an isometric view of an improved waveguide device according to another embodiment of this invention, including the fiber half sandwich of FIG. 12 which has been made according the depiction of FIG. 17;  
         [0106]    [0106]FIG. 19 is an isometric exposed view of the central section of the improved waveguide device according to the invention as shown in FIG. 18, and also showing the improved waveguide;  
         [0107]    [0107]FIG. 20 is an isometric view of an intermediate stage in the production of an improved waveguide device according to another embodiment of this invention including the fiber full sandwich of FIG. 15;  
         [0108]    [0108]FIG. 21 is an isometric view of an improved waveguide device according to another embodiment of this invention including fiber fill sandwich of FIG. 15 which has been made according to the depiction of FIG. 20;  
         [0109]    [0109]FIG. 22 is a side elevational view of the improved waveguide as shown in FIG. 21;  
         [0110]    [0110]FIG. 23 is an isometric view of a fiber full sandwich of another embodiment of this invention, but also showing the partial cut-through embodiment;  
         [0111]    [0111]FIG. 24 is an isometric view of a fiber full sandwich, or of a fiber half sandwich, of other embodiments of this invention, to illustrate the formation of the fiber sandwich with a partial angular cut;  
         [0112]    [0112]FIG. 25 is an isometric view of a fiber full sandwich, or of a fiber half sandwich, of other embodiments of this invention, to illustrate the formation of the fiber sandwich with a fill angular cut;  
         [0113]    [0113]FIG. 26 is an isometric view, looking from the bottom, of another embodiment of the invention having a second trench;  
         [0114]    [0114]FIG. 27 is an isometric view, looking from the bottom, of the embodiment of the invention shown in FIG. 26, with the bottom silicon substrate broken away; and  
         [0115]    [0115]FIG. 28 is an isometric view, looking from the bottom, of the embodiment of the invention shown in FIG. 26, with the bottom silicon substrate broken away; and with the top plate partially broken away.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0116]    As shown in FIG. 1, one embodiment of a silicon substrate for the production of a package for an accurately prepared fiber array comprises a bottom silicon substrate  41  which is provided with an inset strain relief area  42  and with a plurality of parallel V-grooves  45 . The bottom silicon substrate is divided into two sections by a transverse trench  43 . The two sections are a major, or upper, substrate section  46  and a minor, or lower, substrate section  47 .  
         [0117]    [0117]FIG. 1 also shows that the strain relief area extends in the lower substrate section  47 , but also extends beyond the trench  43  into the upper substrate section  46  as strain relief area  42   a.    
         [0118]    The silicon substrate may be etched, laser milled, machined or otherwise processed to produce the bottom silicon substrate  41 , as shown in this embodiment in FIG. 1. Etching is one well-known method for producing V-grooves in silicon with accuracy better than plus/minus 0.5 micrometer or micron (μm).  
         [0119]    The dimensions of the V-grooves  45  and strain relief area  42  depend upon the number of fibers, fiber size and fiber buffer dimensions, but for typical single mode fiber arrays the following numbers are provided as examples.  
         [0120]    The strain relief area  42  is deep and wide enough to accept 250-μm diameter fiber buffer, approximately 130 μm deep.  
         [0121]    The trench  43  is approximately 125 μm wide and 150 μm deep, as it needs to be deeper than the strain relief area in order to serve as a dam for a suitable adhesive, e.g. an epoxy, as well as the break line.  
         [0122]    The V-grooves  45  for holding 125 μm diameter fibers would be 250 μm center-to-center, sized to control the fiber axis height required to generate the desired gap between the top and bottom plates.  
         [0123]    Length L 1  is typically 15 mm and length L 2  is typically 5 mm, although both lengths can be easily changed.  
         [0124]    As seen in FIG. 2 shows the preparation of the bottom plate  241  by placing a fiber array  48  in the bottom of the strain relief areas  42  and  42   a.  Bare fibers  48   a  are disposed in the V-grooves  45 . Bare fibers  48   b  overhang the edge  41   a  of the bottom silicon substrate  41 .  
         [0125]    As shown in FIG. 3, another embodiment of a silicon substrate for the production of a package for an accurately prepared fiber array comprises a bottom silicon substrate  341  which is provided with an inset strain relief area  342  and with a plurality of parallel V-grooves  345 . The bottom silicon substrate  341  is divided into two sections by a transverse trench  343 . The two sections are a major, or upper, substrate section  346  and a minor, or lower, substrate section  347 .  
         [0126]    [0126]FIG. 3 also shows that the strain relief area extends in the lower substrate section  47 , which terminates at the trench  343 .  
         [0127]    As seen in FIG. 4, a fiber array  48  is placed in the bottom of the strain relief area  342 . Bare fibers  48   a  area disposed in the V-grooves  345 . Bare fibers  48   b  overhang the edge  341   a  of the bottom silicon substrate  341 .  
         [0128]    As shown in FIG. 5, another embodiment of a silicon substrate for the production of a package for an accurately prepared fiber array comprises a bottom silicon substrate  541  which is provided with an inset strain relief area  542  and with a plurality of parallel V-grooves  545 . The bottom silicon substrate is divided into two sections by a transverse trench  543 . The two sections are a major, or upper substrate section  546  and minor, or lower, substrate section  547 .  
         [0129]    [0129]FIG. 5 also shows that the parallel V-grooves  545  extend in the upper substrate section  546 , but also extend beyond the trench  543  into the lower substrate section  546  as strain relief area  545   a.    
         [0130]    As seen in FIG. 6, a fiber array  48  is placed in the bottom of the strain relief area  542 . Bare fibers  48   a  area disposed in the V-grooves  545  and V-grooves  545   a.  Bare fibers  48   b  overhang the edge  541   a  of the bottom silicon substrate  541 . The fiber array  48  could also be a number of individual fibers.  
         [0131]    [0131]FIG. 7 shows the bottom plate of FIG. 2 in a side-by-side relationship with the upper silicon substrate of FIG. 1. In this FIG, the upper silicon substrate is identified by the generic reference number  70 A and the lower plate is identified by the generic reference number  70 B.  
         [0132]    Thus, it is seen that upper silicon substrate  70 A includes (as previously described) bottom silicon substrate  41  which is provided with an inset relief area  42  and with a plurality of parallel V-groove  45 . The bottom silicon substrate  41  is divided into two sections by a transverse trench  43 . These two sections area a major, or upper, section  46 , and a minor, or lower section  47 . The strain relief area  42  extends in the lower substrate section  47  and also extends beyond the trench  43  into the upper substrate section  46  as strain relief section  42   a.    
         [0133]    It is also seen that the bottom plate  70 B includes a fiber array  48  which is placed in the bottom of the strain relief areas  42  and  42   a.  Bare fibers  48   a  are disposed in the V-grooves  45 . In addition, bare fibers  48   b  overhang the edge  41   a  of the bottom silicon substrate  41 .  
         [0134]    As seen in FIG. 8, the upper silicon substrate  70 A is placed atop the bottom plate  70 B so that the V-grooves  45  align with the bare fibers  48   a,  so that the fiber array aligns with the strain relief area  42  and so that the trenches  43  area substantially aligned.  
         [0135]    As seen in FIG. 9, extremely thick non-wicking adhesive, e.g., epoxy  91 , is used to bond the edges of the upper silicon substrate  70 A to the upper face of the bottom plate  70 B, to form a sandwich  70 C of an embodiment of this invention.  
         [0136]    [0136]FIGS. 9,10 and  11  show the production of fiber sandwich of an embodiment of this invention where only the bottom half of the bare fibers  48   a  are exposed. As shown in FIG. 9, the sandwich  70  C is cut completely through along the line  93 . The angle alpha (see FIG. 11) depends on the specific requirements. For example, it could be in the range of 90 degrees or in the range of 80 to 85 degrees or in the range of 95 to 100 degrees. The angle beta (see FIG. 10) is preferably 90 degrees to the axis of the fibers.  
         [0137]    At this point, the upper silicon substrate  70 A and the bottom plate  70 B may be temporality be clamped together, and the severed ends of the bare fibers may be polished.  
         [0138]    The next stage in the manufacturing procedure is the formation of the half-sandwich of an embodiment of this invention. This is shown in FIG. 12 , FIG. 13 and FIG. 14.  
         [0139]    As seen in these FIGS, the major section  46  (see FIG. 1) of the bottom plate  70 B is broken away at trench  43 . This forms half-sandwich  70 D, which consists of major section  46  of bottom plate  70 B, fiber array  48  and exposed bare fibers  48   a.    
         [0140]    The next stage in the manufacturing procedure is the formation of the full sandwich of an embodiment of this invention. This is shown in FIG. 15 and FIG. 16.  
         [0141]    As seen in these FIGS, the major section  46  (see FIG.1) of the half-sandwich  70 D is broken away at trench  43 . This forms full sandwich  70 E, which consists of minor section  47  (see FIG. 1) of upper silicon substrate  70 A, fiber array  48  and exposed bare fibers  48   a.    
         [0142]    Another embodiment of the invention is shown in FIG. 17, FIG. 18 and FIG. 19. In these FIGS, a waveguide according to an embodiment of the invention is produced.  
         [0143]    As seen in these FIGS, the waveguide  1700  consists of a suitable substrate  1702  within which are a plurality of lateral, fiber-mating areas,  1704   1706 , which may be V-grooves or other aligning structures. Two half-sandwiches  70 D (only one of which is shown) are superposed atop the fiber-mating areas  1704 ,  1706 , so that the exposed fibers  48   a  mate within the fiber-mating areas  1704 ,  1706 .  
         [0144]    [0144]FIG. 19 shows the central area  1708  of the waveguide  1700 . That central section  1708  comprises the suitable substrate  1702  which is provided with a transverse trench  1710 . The suitable substrate is also provided with a plurality of longitudinal, conventional fibers  1714 , to which the bare exposed fibers  48   a  (in FIG. 18) of the half-sandwich are to be coupled.  
         [0145]    Another embodiment of the invention is shown in FIG. 20. In this FIG, a waveguide according to an embodiment of the invention is produced.  
         [0146]    As seen in this FIG, the waveguide  2000  consists of a suitable substrate  2002  within which are plurality of longitudinal fiber-mating areas,  2004   2006 , which may be V-grooves or other aligning structures. Two full sandwiches  70 E (only one of which is shown) are superposed atop the fiber-mating areas  2004 ,  2006 , so that the exposed fibers  48   a  mate within the fiber-mating areas  1704 ,  1706 .  
         [0147]    The central area  2008  of the waveguide  2000  is identical to the central area  170  shown in FIG. 19, and so will not be described further.  
         [0148]    Another embodiment of the invention is shown in FIG. 21 and FIG. 22, and starts with the sandwich shown in FIG. 9.  
         [0149]    In this embodiment, the cut  2102  is made to cut completely through the bare exposed fibers  48   a,  but only to cut a trench  2104  in the bottom plate  70 A. The cut  2102  is tilted at an angle gamma to the vertical, as shown in FIG. 22. Then, the unglued portion  2106  of the upper silicon plate  70 A is broken away at the trench  43 , to provide full sandwich (not seen). This sandwich contains the exposed portion of the bottom plate  70 A, and the minor section  47  of the upper silicon plate  70 B, as well as silicon substrate remnant  2108 .  
         [0150]    Another embodiment of the invention is shown in FIG. 23 and the use thereof to provide another embodiment of a waveguide is shown in FIG. 24. These embodiments of the invention start with the sandwich shown in FIG. 9.  
         [0151]    In the embodiment shown in FIG. 23, the partial cut  2302  is made to cut completely through the bare exposed fibers  48   a,  but only to cut a trench  2304  in the bottom plate  70 A. The cut  2302  is cut at an angle delta to the central longitudinal axis of the sandwich  70 C. The cut  2302  may be a completely vertical cut, or, as described in FIG. 22, may be tiled at an angle gamma to the vertical, as shown in FIG. 22. Then, the unglued portion  2308  of the lower silicon plate  70 B is broken away at the trench  43 , to provide a half sandwich (not seen in this figure but seen in FIG. 24). This sandwich contains the exposed portion of the upper plate  70 A, and the minor section  47  of the bottom silicon plate  70 B, as well as a silicon substrate remnant  2308 .  
         [0152]    [0152]FIG. 24 shows the production of a waveguide of an embodiment of the invention which is similar in most respects to the production of the embodiment of the waveguide shown in FIG. 17, FIG. 18 and FIG. 19. The only difference is that the abutting edges of the fill sandwich  70 F and the central portion  48  of the waveguide  2400  must be cut at the same angle.  
         [0153]    Another embodiment of the invention is shown in FIG. 25 and starts with the sandwich shown in FIG. 9.  
         [0154]    In this embodiment, the cut  2502  is made to cut completely through both bare exposed fibers  48   a,  and the bottom plate  70 A, leaving the ends of the bare exposed fibers  48   a  visible at the cut edges  41   a  and  48   a.  The cut shown in broken lines at  2502  is vertical, but is disposed at an angle of theta to the central longitudinal axis of the upper silicon substrate  70 A. The remaining steps of producing the sandwiches shown in FIGS.  12  to  16  are the same as previously described.  
         [0155]    The use of the embodiment of FIG. 25 to make a waveguide of an embodiment of this invention is similar to the production of the embodiment of the waveguide shown in FIG. 24. The only difference is that the sandwich is different. However, the abutting edges of the sandwich and the central portion of the waveguide must be cut at the same angle.  
         [0156]    Another embodiment of the invention is shown in FIG. 26, FIG. 27 and FIG. 28 and starts with the embodiment of FIG. 7.  
         [0157]    In this embodiments, the upper silicon substrate  70 A has a second trench  2643  made therein. Then the processing proceeds as shown in FIG. 27 and  28  to form a half-sandwich as previously described in FIGS.  9  to  14 . Then the top plate upper silicon substrate  2649  can be broken away, leaving a half-sandwich  70 C with a length of bare exposed fibers  48   b  fully exposed.  
         [0158]    It should be obvious to a person skilled in the art that the plates could be fabricated from any material that can be processed within precision tolerances, and that can break cleanly and consistently at a trench. Although it is not as efficient, it would be possible to cut away the plate at the trench using a saw or other such device. It should also be obvious to person skilled in the art that the positioning grooves in the top and bottom plates may take the form of U-grooves, or other like shapes that provide the support and precision required for aligning optical fibers. Further, the fibers could be fixed in the grooves by materials such as wax, easily dissolved adhesives or the like, which would be removed prior to breaking away the plates. In the case of the half-sandwich, the fibers could be fixed to the top late with an adhesive or the like, prior to cutting the fibers and breaking away the bottom plate.  
       CONCLUSION  
       [0159]    From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Consequently, such changes and modifications are properly, equitably, and “intended” to be, within the full range of equivalence of the following claims.