Abstract:
A fiber optic device with connection regions in grooves of a substrate is provided. In one aspect, the device is a fiber optic coupler assembly and each groove receives fiber optic cables in the connection region to form couplings. In another aspect, each groove receives cables for connection to an electronic component. In one embodiment, the device includes a substrate with an elongate member having grooves along an exterior surface. In another embodiment, the device includes a substrate with multiple elongate members, each having a groove along an interior surface. A method for assembling the device includes: a) receiving cables in a first groove; b) connecting the fibers of each cable together in a connecting region of the first groove; c) selecting at least one cable from the first coupling and severing the selected cable(s); and d) performing steps a) through c) for a second groove.

Description:
BACKGROUND OF INVENTION  
         [0001]    The invention relates to fiber optic devices, such as fiber optic couplers. More particularly, the present invention relates to a fiber optic device with multiple independent connecting regions, each connecting region for receiving multiple optical fibers, and a method for making same. However, it is to be appreciated that the invention is also amenable to other applications.  
           [0002]    A fiber optic coupler is a device that can distribute the optical signal (power) from, for example, one fiber among two or more fibers. A fiber optic coupler can also combine the optical signal from, for example, two or more fibers into a single fiber. Fiber optic couplers have been used in optical communications, optical sensors, and fiber optic gyroscopes. Fiber optic couplers can be either active or passive devices. The difference between active and passive couplers is that a passive coupler redistributes the optical signal without optical-to-electrical conversion. Active couplers are electronic devices that split or combine the signal electrically and use fiber optic detectors and sources for input and output.  
           [0003]    [0003]FIG. 1 illustrates the design of a basic fiber optic coupler  10 . A basic fiber optic coupler  10  has N input ports  12  and M output ports  14 . N and M typically range from 1 to 64. The number of input ports  12  and output ports  14  vary depending on the intended application for the coupler  10 . Types of fiber optic couplers  10  include optical splitters, optical combiners, X couplers, star couplers, and tree couplers.  
           [0004]    An optical splitter is a passive device that splits the optical power carried by a single input fiber into, for example, two output fibers. The input optical power is normally split evenly between the two output fibers. This type of optical splitter is known as a Y-coupler. However, an optical splitter may distribute the optical power carried by input power in an uneven manner. An optical splitter may split most of the power from the input fiber to one of the output fibers. In this case, only a small amount of the power is coupled into the secondary output fiber. This type of optical splitter is known as a T-coupler, or an optical tap. An optical combiner is a passive device that combines the optical power carried by, for example, two input fibers into a single output fiber.  
           [0005]    An X coupler combines the functions of the optical splitter and combiner. The X coupler combines and divides the optical power from, for example, the two input fibers between the two output fibers. Another name for the X coupler is the 2X2 coupler. Star and tree couplers are multiport couplers that have more than two input or two output ports. A star coupler is a passive device that distributes optical power from, for example, more than two input ports among several output ports. A tree coupler is a passive device that splits the optical power from one input fiber to more than two output fibers. A tree coupler may also be used to combine the optical power from more than two input fibers into a single output fiber. Star and tree couplers distribute the input power uniformly among the output fibers.  
           [0006]    Generally, fiber optic couplers must prevent the transfer of optical power from one input fiber to another input fiber. Directional couplers are fiber optic couplers that prevent this transfer of power between input fibers. Many fiber optic couplers are also symmetrical. A symmetrical coupler transmits the same amount of power through the coupler when the input and output fibers are reversed.  
           [0007]    There are several common techniques for fabricating passive fiber optic couplers. Some fiber optic coupler fabrication involves beam splitting using micro lenses or graded-refractive-index (GRIN) rods and beam splitters or optical mixers. These beam splitter devices divide the optical beam into two or more separated beams. Fabrication of fiber optic couplers may also involve twisting, fusing, and tapering together two or more optical fibers. This type of fiber optic coupler is a fused biconical taper coupler. Fused biconical taper couplers use the radiative coupling of light from the input fiber to the output fibers in the tapered region to accomplish beam splitting.  
           [0008]    Fiber optic couplers are very sensitive to environmental influences because the optical material of which the optical fibers are made is very fragile. In addition, the coupling region is not provided with a jacket so adverse environments influence the quality of the optical material of the fiber optic coupler and/or the signals transmitted through the fiber optic coupler. Therefore, the optical signal processing performance of a fiber optic coupler in various environments typically depends upon the type of housing or package in which it is positioned for protection and on the method used to assemble the packaged fiber optic coupler. A problem with fused fiber optic couplers is latent failure of the coupler fiber or fibers inside the coupler enclosure or package due to stresses induced on the fiber from abuse such as pulls, tugs, jerks and yanks on the fiber from outside of the coupler package. The fused and tapered portions of the coupler where the transfer of optical power takes place is structurally weak and sensitive to such abuse, in addition to changes in environmental conditions.  
           [0009]    Packaging techniques which have been used to protect the fiber optic coupler from such deleterious influences include the use of a slotted substrate, typically of quartz, silicon, sapphire, or ceramic material, as a protective covering and a support for the coupled region of a fiber optic coupler. In such an arrangement, the coupled region is typically placed within a central open portion of the substrate and epoxy is applied at the ends of the substrate to secure the optical fibers to the substrate.  
           [0010]    Although end-to-end coupling devices for a plurality of fiber optics have been developed using a variety of differing approaches, including grooved block assemblies (see, for example, U.S. Pat. No. 5,402,512 to Jennings et al., U.S. Pat. No. 5,757,997 to Birrell et al., and U.S. Pat. No. 6,151,433 to Dower et al.), prior art disclosing an assembly for accommodating a large number of optical fiber couplers is very limited (see, for example, U.S. Pat. No. 4,514,057 to Palmer et al.), and no known prior art discloses an assembly accommodating multiple fiber optic couplers with substrates to support the fibers in the coupling region. In fact, most fiber optic couplers involve a relatively small number of fibers encased within a coupling package and are incapable of providing for a large number of independent optical couplers. Examples of these types of couplers and packages are shown in U.S. Pat. No. 6,085,001 to Belt, U.S. Pat. No. 6,148,129 to Pan et al., and U.S. Pat. No. 6,167,176 to Belt.  
           [0011]    Heightening demands for fiber optic applications, particularly fiber optic communications, have led to demands for miniaturization, durability, and high reliability of fiber optic devices, including fiber optic couplers.  
         SUMMARY OF THE INVENTION  
         [0012]    Thus, there is a need for a fiber optic device capable of providing multiple independent connecting regions, each connecting region for receiving multiple optical fibers, the device having sufficient durability and reliability characteristics in view of fiber optic industry demands.  
           [0013]    In one aspect of the invention, a fiber optic coupler assembly is provided. The fiber optic coupler assembly includes a substrate with at least two optically isolated grooves; at least two fiber optic cables disposed in each groove; and an enclosure for packaging the substrate and cables.  
           [0014]    In another aspect of the invention, a fiber optic device is provided. The fiber optic device includes a substrate with at least two optically isolated grooves; at least one electronic component disposed in each groove; at least two fiber optic cables disposed in each groove; and an enclosure for packaging the substrate, electronic components, and cables.  
           [0015]    In yet another aspect of the invention, a method for assembling a fiber optic coupler assembly is provided. The method includes the steps of: a) receiving at least two fiber optic cables in a first optically isolated groove of a substrate, each cable having a fiber jacket of the cable removed from a middle portion of the cable to expose an optical fiber; b) connecting the exposed optical fibers of each cable together in a connecting region of the first groove to form a first fiber optic coupling with at least four coupled fiber optic cables extending therefrom, each coupled fiber optic cable having a connection end joined in the first coupling and a lead end extending outward from the first groove; c) selecting at least one of the coupled fiber optic cables from the first coupling and severing the selected coupled fiber optic cable(s) from the first coupling; d) receiving at least two fiber optic cables in a second optically isolated groove of the substrate, each cable having a fiber jacket of the cable removed from a middle portion of the cable to expose an optical fiber, e) connecting the exposed optical fibers of each cable together in a connecting region of the second groove to form a second fiber optic coupling with at least four coupled fiber optic cables extending therefrom, each coupled fiber optic cable having a connection end joined in the second coupling and a lead end extending outward from the second groove; and f) selecting at least one of the coupled fiber optic cables from the second coupling and severing the selected coupled fiber optic cable(s) from the second coupling.  
           [0016]    In still another aspect of the invention, a method for assembling a fiber optic device is provided. The method includes the steps of: a) receiving at least two fiber optic cables in a first optically isolated groove of a substrate, each cable having a connection end and a lead end, each cable having a fiber jacket removed from the connection end of the cable to expose an optical fiber within the cable, wherein at least one electronic component is disposed in the first groove; b) connecting the exposed optical fibers from the connection end of each cable to predetermined points on the electronic component(s) in a connecting region of the first groove; c) receiving at least two fiber optic cables in a second optically isolated groove of the substrate, each cable having a connection end and a lead end, each cable having a fiber jacket removed from the connection end of the cable to expose an optical fiber within the cable, wherein at least one electronic component is disposed in the second groove; and d) connecting the exposed optical fibers from the connection end of each cable to predetermined points on the electronic component(s) in a connecting region of the second groove.  
           [0017]    Accordingly, one object of the invention is to provide a fiber optic device with multiple connecting regions. Each connecting region capable of receiving multiple optical fibers and, in one aspect, independent fiber optic couplings. An advantage of the invention is its contribution to miniaturization of fiber optic equipment. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0018]    The invention is described in more detail in conjunction with a set of accompanying drawings.  
         [0019]    [0019]FIG. 1 is a block diagram of a prior art fiber optic coupler.  
         [0020]    [0020]FIG. 2 provides geometric views of a substrate for a fiber optic device in one embodiment of the invention.  
         [0021]    [0021]FIG. 3 provides geometric views of a substrate for a fiber optic device in another embodiment of the invention.  
         [0022]    [0022]FIG. 4 provides geometric views of a substrate for a fiber optic device in still another embodiment of the invention.  
         [0023]    [0023]FIG. 5 provides geometric views of a substrate for a fiber optic device in yet another embodiment of the invention.  
         [0024]    [0024]FIG. 6 provides geometric views and a cross-sectional view of a fiber optic device using a substrate in the embodiment shown in FIG. 2.  
         [0025]    [0025]FIG. 7 provides geometric views of a substrate for a fiber optic device in one embodiment of the invention.  
         [0026]    [0026]FIG. 8 provides geometric views of a substrate for a fiber optic device in another embodiment of the invention.  
         [0027]    [0027]FIG. 9 provides geometric views and a cross-sectional view of a fiber optic device using the substrate in the embodiment shown in FIG. 7. 
     
    
     DETAILED DESCRIPTION  
       [0028]    While the invention is described in conjunction with the accompanying drawings, the drawings are for purposes of illustrating exemplary embodiments of the invention and are not to be construed as limiting the invention to such embodiments. It is understood that the invention may take form in various components and arrangements of components, and in various steps and arrangements of steps beyond those provided in the drawings and associated description. Within the drawings, like reference numerals denote like elements. Additionally, similar items are identified from drawing to drawing with reference numbers bearing the same two least significant digits with the most significant digit changing from drawing to drawing to indicate a minor difference between the items.  
         [0029]    Referring to FIG. 2, geometric views of a substrate for a fiber optic device in one embodiment of the invention are provided. An isometric view and a cross-sectional view of the substrate  220  are shown. The substrate  220  is comprised of an elongate member  222  with two grooves  224 ,  225 . The grooves  224 ,  225  are substantially parallel to a longitudinal axis of the elongate member  222 . The elongate member  222  has a generally cylindrical shape. The elongate member  222  is defined by an elongate surface  226  and two ends  228 ,  229 . The elongate surface  226  is further defined by the generally cylindrical shape of the elongate member  222  and the two grooves  224 ,  225   
         [0030]    The elongate surface  226  is still further defined by four surface portions: 1) a first exterior surface  230  defined by the generally cylindrical shape of the elongate member  222 , 2) a second exterior surface  232  defined by the generally cylindrical shape of the elongate member  222 , 3) a first recessed surface  234  defined by the shape of the groove  224 , and 4) a second recessed surface  236  defined by the shape of the groove  225 . As shown, the two recessed surfaces  234 ,  236  are substantially the same dimension and disposed on opposing sides of the elongate member  222 . Likewise, as shown, the two exterior surfaces  230 ,  232  are substantially the same dimension and disposed on opposing sides of the elongate member  222 . Accordingly, as shown, the elongate surface  226  is generally symmetrical. Alternatively, the grooves  224 ,  225  of the substrate  220  can have different dimensions, different shapes, be disposed at different angles to each other, or any combination thereof, creating numerous additional embodiments of the invention.  
         [0031]    The recessed surfaces  234 ,  236  are further described in reference to the cross-sectional view of the substrate  220 . As shown, the recessed surfaces  234 ,  236  are generally defined by an inverted conical shape. However, the inverted conical shape is modified by flattening an end  238  of the conical shape so that the flattened end  238  is generally parallel to a line  239  intersecting the end of both legs  240 ,  242  of the conical shape. More specifically, the first recessed surface  234  is defined by three surface portions: 1) a first linear surface  240  is recessed from the first exterior surface  230  in accordance with the inverted conical shape, 2) a second linear surface  242  is recessed from the second exterior surface  232  in accordance with the inverted conical shape, and 3) a flattened end surface  238  is attached to both the first and second linear surfaces  240 ,  242  and parallel to a line  239  intersecting the point at which the first linear surface  240  is attached to the first exterior surface  230  and the point at which the second linear surface  242  is attached to the second exterior surface  232 .  
         [0032]    Referring to FIG. 3, geometric views of a substrate for a fiber optic device in another embodiment of the invention are provided. An isometric view and a cross-sectional view of the substrate  320  are shown. The substrate  320  is comprised of an elongate member  322  with two grooves  324 ,  325 . The grooves  324 ,  325  are substantially parallel to a longitudinal axis of the elongate member  322 . The elongate member  322  has a generally cylindrical shape. The elongate member  322  is defined by an elongate surface  326  and two ends  328 ,  329 . The elongate surface  326  is further defined by the generally cylindrical shape of the elongate member  322  and the two grooves  324 ,  325 .  
         [0033]    The elongate surface  326  is still further defined by four surface portions: 1) a first exterior surface  330  defined by the generally cylindrical shape of the elongate member  322 , 2) a second exterior surface  332  defined by the generally cylindrical shape of the elongate member  322 , 3) a first recessed surface  334  defined by the shape of the groove  324 , and 4) a second recessed surface  336  defined by the shape of the groove  325 . As shown, the two recessed surfaces  334 ,  336  are substantially the same dimension and disposed on opposing sides of the elongate member  322 . Likewise, as shown, the two exterior surfaces  330 ,  332  are substantially the same dimension and disposed on opposing sides of the elongate member  322 . Accordingly, as shown, the elongate surface  326  is generally symmetrical. Alternatively, the grooves  324 ,  325  of the substrate  320  can have different dimensions, different shapes, be disposed at different angles to each other, or any combination thereof, creating numerous additional embodiments of the invention.  
         [0034]    The recessed surfaces  334 ,  336  are further described in reference to the cross-sectional view of the substrate  320 . As shown, the recessed surfaces  334 ,  336  are generally defined by an inverted half rectangular shape. More specifically, the first recessed surface  334  is defined by three surface portions: 1) a first linear surface  340  is recessed from the first exterior surface  330  in accordance with the inverted half rectangular shape, 2) a second linear surface  342  is recessed from the second exterior surface  332  and parallel to the first linear surface  340  in accordance with the inverted half rectangular shape, and 3) a third linear surface  338  is attached and perpendicular to both the first and second linear surfaces  340 ,  342  in accordance with the inverted half rectangular shape.  
         [0035]    Referring to FIG. 4, geometric views of a substrate for a fiber optic device in still another embodiment of the invention are provided. An isometric view and a cross-sectional view of the substrate  420  are shown. The substrate  420  is comprised of an elongate member  422  with two grooves  424 ,  425 . The grooves  424 ,  425  are substantially parallel to a longitudinal axis of the elongate member  422 . The elongate member  422  has a generally cylindrical shape. The elongate member  422  is defined by an elongate surface  426  and two ends  428 ,  429 . The elongate surface  426  is further defined by the generally cylindrical shape of the elongate member  422  and the two grooves  424 ,  425 .  
         [0036]    The elongate surface  426  is still further defined by four surface portions: 1) a first exterior surface  430  defined by the generally cylindrical shape of the elongate member  422 , 2) a second exterior surface  432  defined by the generally cylindrical shape of the elongate member  422 , 3) a first recessed surface  434  defined by the shape of the groove  424 , and 4) a second recessed surface  436  defined by the shape of the groove  425 . As shown, the two recessed surfaces  434 ,  436  are substantially the same dimension and disposed on opposing sides of the elongate member  422 . Likewise, as shown, the two exterior surfaces  430 ,  432  are substantially the same dimension and disposed on opposing sides of the elongate member  422 . Accordingly, as shown, the elongate surface  426  is generally symmetrical. Alternatively, the grooves  424 ,  425  of the substrate  420  can have different dimensions, different shapes, be disposed at different angles to each other, or any combination thereof, creating numerous additional embodiments of the invention.  
         [0037]    The recessed surfaces  434 ,  436  are further described in reference to the cross-sectional view of the substrate  420 . As shown, the recessed surfaces  434 ,  436  are generally defined by an inverted half circular shape. However, the inverted half circular shape is modified by extending the ends of the inverted half circular shape along lines tangential to the ends of the inverted half circular shape. More specifically, the first recessed surface  434  is defined by three surface portions: 1) a first arcuate surface  438  in accordance with the inverted half circular shape, 2) a second linear surface  440  is recessed from the first exterior surface  430  and attached to a first end  439  of the first arcuate surface  438  so that the second linear surface  440  has a tangential relationship to the first end  439  of the first arcuate surface  438 , and 3) a third linear surface  442  is recessed from the second exterior surface  432  and attached to a second end  441  of the first arcuate surface  438  so that the third linear surface  442  has a tangential relationship to the second end  441  of the first arcuate surface  438 .  
         [0038]    Referring to FIG. 5, geometric views of a substrate for a fiber optic device in yet another embodiment of the invention are provided. An isometric view and a cross-sectional view of the substrate  520  are shown. The substrate  520  is comprised of an elongate member  522  with two grooves  524 ,  525 . The grooves  524 ,  525  are substantially parallel to a longitudinal axis of the elongate member  522 . The elongate member  522  has a generally rectangular cross-sectional shape. The elongate member  522  is defined by an elongate surface  526  and two ends  528 ,  529 . The elongate surface  526  is further defined by the generally rectangular shape of the elongate member  522  and the two grooves  524 ,  525 .  
         [0039]    The elongate surface  526  is still further defined by six surface portions: 1) a first exterior surface  530  defined by the generally rectangular shape of the elongate member  522 , 2) a second exterior surface  532  defined by the generally rectangular shape of the elongate member  222 , 3) a third exterior surface  531  defined by the generally rectangular shape of the elongate member  222 , 4) a fourth exterior surface  533  defined by the generally rectangular shape of the elongate member  222 , 5) a first recessed surface  534  defined by the shape of the groove  524 , and 4) a second recessed surface  536  defined by the shape of the groove  525 . As shown, the two recessed surfaces  534 ,  536  are substantially the same dimension and disposed on opposing sides of the elongate member  222 . Likewise, as shown, each of the opposing exterior surfaces  530 ,  532  and  531 ,  533  are substantially the same dimension as the exterior surface disposed on the opposing side of the elongate member  522 . Accordingly, as shown, the elongate surface  526  is generally symmetrical. Alternatively, the grooves  524 ,  525  of the substrate  520  can have different dimensions, different shapes, be disposed at different angles to each other, or any combination thereof, creating numerous additional embodiments of the invention.  
         [0040]    The recessed surfaces  534 ,  536  are further described in reference to the cross-sectional view of the substrate  520 . As shown, the recessed surfaces  534 ,  536  are generally defined by an inverted conical shape. However, the inverted conical shape is modified by flattening an end  538  of the conical shape so that the flattened end  538  is generally parallel to a line  239  intersecting the end of both legs  540 ,  542  of the conical shape. More specifically, the first recessed surface  534  is defined by three surface portions: 1) a first linear surface  540  is recessed from the first exterior surface  530  in accordance with the inverted conical shape, 2) a second linear surface  542  is recessed from the second exterior surface  532  in accordance with the inverted conical shape, and 3) a flattened end surface  538  is attached to both the first and second linear surfaces  540 ,  542  and parallel to a line  239  intersecting the point at which the first linear surface  540  is attached to the first exterior surface  530  and the point at which the second linear surface  542  is attached to the second exterior surface  532 .  
         [0041]    Referring to FIGS. 2 and 5, one of ordinary skill in the art will recognize the similarities of substrate  220  and substrate  520  due to the common shapes (e.g., inverted conical) of the grooves  224 ,  225  of FIG. 2 and the grooves  524 ,  525  of FIG. 5. Just as the different shapes of the substrate  220  of FIG. 2 (e.g., generally cylindrical) and the substrate  520  of FIG. 5 (e.g, generally rectangular) can incorporate the same shaped groove (e.g., inverted conical), so also can various other shapes of the substrate (e.g., substrates with oval, triangular, square, pentagonal, hexagonal, octagonal, etc. shaped cross-sections) incorporate inverted conical shaped grooves.  
         [0042]    Additionally, referring to FIGS.  3 - 5 , the inverted half rectangle shaped grooves of FIG. 3 and the inverted half circular shaped grooves of FIG. 4 can be incorporated in the rectangular shaped substrate of FIG. 5. Likewise, the inverted half rectangle shaped grooves of FIG. 3 and the inverted half circular shaped grooves of FIG. 4 can also be incorporated in various other shapes of substrates (e.g., substrates with oval, triangular, square, rectangular, pentagonal, hexagonal, octagonal, etc. shaped cross-sections).  
         [0043]    Referring to FIGS.  2 - 5 , the substrates  220 ,  320 ,  420 , and  520  can be made from glass, silicon, sapphire, ceramic, or other suitable materials. Preferably, glass (e.g., Clear-Strate™ fused quartz by Quality Quartz of America, Inc.), generically known as vitreous silica, is used to make the substrate. The substrate can be formed by machining, extruding, or other suitable methods. The length  244  of the substrate  220 ,  320 ,  420 ,  520  can range from 5 mm to 100 mm with a typical tolerance of +/−0.25 mm. The outside diameter  246  of the substrate  220 ,  320 , and  420  can range from 1 mm to 5 mm with a typical tolerance of +/−0.10 mm. The exterior width  546  of the substrate  520  can range from 1 mm to 3.5 mm with a typical tolerance of +/−0.10 mm. The upper width  248  of the groove may have a typical tolerance of +/−0.10 mm. The lower width  250  of the groove may have a typical tolerance of +/−0.10 mm. The depth  252  of the groove may have a typical tolerance of +/−0.10 mm. Alternate dimensions and tolerances, suitable for use in fiber optic devices, will be clear to those skilled in the art upon reading this disclosure. Such alternate dimensions and tolerances are considered within the scope of this disclosure and the attached claims.  
         [0044]    Referring to FIG. 6, geometric views and a cross-sectional view of a fiber optic device using the substrate in the embodiment shown in FIG. 2 are provided. The fiber optic device  610  is comprised of two fiber optic input cables  612 , four fiber optic output cables  614 , and a substrate  620 . As shown, the substrate  620  is like the substrate  220  described above in reference to FIG. 2 and made from, for example, Clear-Strate™ fused quartz. However, the substrate  620  and its grooves can have a cross-section in various other shapes (e.g., substrate  320 ,  420 ,  520 , and others, as described above). Each fiber optic cable  612 ,  614  is comprised of an optical fiber  615  clad in a fiber jacket  616  with a connection end  617  and a lead end  618 . A length of the fiber jacket  616  is removed from a predetermined portion of the connection end  617 . The substrate  620  includes two optically isolated grooves  624 ,  625 , each groove (e.g.,  624 ) receiving one fiber optic input cable  612  and two fiber optic output cables  614 . The fiber jacket  616  of each fiber optic cable  612 ,  614  is disposed in an end portion of the groove  624 ,  625  and may be secured in position with an epoxy  621  or equivalent adhesive. The epoxy  621  or equivalent adhesive provides a form of strain relief to the fiber optic cable  612 ,  614  and a form of protection to the interior connections of the optical fibers  615 . The optical fiber  615  of each fiber optic cable  612 ,  614  is disposed in a connection region  654 ,  655  of the groove  624 ,  625  and may be secured in position with a suitable adhesive  623  or an equivalent material compatible with the materials of the optical fiber  615  and the substrate  620 . The adhesive  623  or equivalent material provides support for the optical fibers  615 .  
         [0045]    As shown, the optical fibers  615  from one fiber optic input cable  612  and two fiber optic output cables  614  in a first connection region  654  are connected to each other forming a first coupling. The optical fibers  615  from the one fiber optic input cable  612  and the two fiber optic output cables  614  in a second connection region  655  are connected to each other forming a second coupling. The substrate  620  and the connection ends  618  of the fiber optic cables  612 ,  614  are packaged in an enclosure  627 . The enclosure  627  may be adapted for use with strain relief boots  656 ,  657  on each end of the enclosure  627 . Openings in the strain relief boots  656 ,  657  receive the fiber optic cables  612 ,  614  and provide strain relief to protect the interior connections of the optical fibers  615 .  
         [0046]    The fiber optic device  610  of FIG. 6 may be assembled using four fiber optic cables. A length of the fiberjacket  616  is removed from a middle portion of each cable to expose the optical fiber  615 . The first optically isolated groove  624  receives two of the fiber optic cables such that the exposed optical fibers  615  are disposed in the first connection region  654 . The two exposed optical fibers  615  are connected together in the first connection region  654  forming a first coupling with four fiber optic cables, each cable having a connection end  617  connected to form the first coupling and a lead end  618  extending outward from the first coupling. One of the fiber optic cables is selected and severed from the first coupling, leaving the lead ends  618  of one fiber optic input cable  612  and two fiber optic output cables  614  extending from opposing ends of the first optically isolated groove  624 . The second optically isolated groove  625  receives the other two fiber optic cables such that the exposed optical fibers  615  are disposed in the second connection region  655 . These two exposed optical fibers  615  are connected together in the second connection region  655  forming a second coupling with four fiber optic cables, each cable having a connection end  617  connected to for the second coupling and a lead end  618  extending outward from the second coupling. One of the fiber optic cables is selected and severed from the second coupling, leaving the lead ends  618  of one fiber optic input cable  612  and two fiber optic output cables  614  extending from opposing ends of the second optically isolated groove  625 . The substrate  620  and the couplings are packaged in the enclosure  627 .  
         [0047]    As described, the fiber optic device  610  of FIG. 6 is a fiber optic coupler assembly with two optically isolated couplings. As shown, both couplings are commonly known as 1×2 dividers. Alternatively, simply by reversing the input and output ports, in other words defining item  612  as fiber optic output cables and item  614  as fiber optic input cables, both couplings are commonly known as 2×1 combiners. In alternate configurations, the fiber optic device can have multiple input ports (e.g., 1 to 64) and multiple output ports (e.g., 1 to 64) for each optically isolated coupling  
         [0048]    In still further alternative configurations, the fiber optic device  610  can include one or more additional components (e.g., waveguides and/or semiconductor devices) and each of the optical fibers  615  can be connected to a predetermined point on the additional component(s). These alternate configurations are examples of using the substrate  620  made from, for example, Clear-Strate™ fused quartz in optical switches, wavelength-division multiplexers, and optical repeaters. The additional component(s) are disposed in the connection region  654 ,  655  of at least one of the optically isolated grooves  624 ,  625  of the substrate  620 . Assuming at least one additional component is disposed in each of the grooves  624 ,  625 , the fiber optic device  610  of FIG. 6 may be assembled using four or more fiber optic cables. A length of the fiber jacket  616  is removed from a connection end  617  of each cable to expose the optical fiber  615 . The first optically isolated groove  624  receives at least two fiber optic cables such that the connection ends  617  are disposed in the first connection region  654 . The connection ends  617  are connected to predetermined points on the additional component(s) with the lead ends  618  extending outward from the substrate  620 . The second optically isolated groove  625  also receives at least two fiber optic cables such that the connection ends  617  are disposed in the second connection region  655 . The connection ends  617  are connected to predetermined points on the additional component(s) with the lead ends  618  extending outward from the substrate  620 . The substrate  620  and additional component(s) are packaged in the enclosure  627 .  
         [0049]    Referring to FIG. 7, geometric views of a substrate for a fiber optic device in one embodiment of the invention is provided. An isometric view and a cross-sectional view of the substrate  720  is shown. The substrate  720  is comprised of two elongate members  722 ,  758 . Each elongate member (e.g.,  722 ) has a mating surface facing the associated elongate member. There is a groove  724  in the mating surface of the elongate member  722 . The groove  724  is substantially parallel to a longitudinal axis of the elongate member  722 . For alignment, the mating surface may also include nubs and corresponding slots in the associated mating surface, slots and corresponding nubs in the associated mating surface, ridges and corresponding grooves in the associated mating surface, grooves and corresponding ridges in the associated mating surface, other types of suitable alignment features, or any combination thereof  
         [0050]    The elongate member  722  has a generally half cylindrical shape. The elongate member  722  is defined by an elongate surface  726  and two ends  728 ,  729  The elongate surface  726  is further defined by the generally half cylindrical shape of the elongate member  722  and the groove  724 . The elongate surface  726  is still further defined by two surface portions: 1) an exterior surface  730  defined by the generally half cylindrical shape of the elongate member  722  and 2) a mating surface. The mating surface is defined by a first interior surface  735  and a second interior surface  737  based on the generally half cylindrical shape of the elongate member  722  and a recessed surface  734  defined by the shape of the groove  724 .  
         [0051]    The recessed surface  734  is further described in reference to the cross-sectional view of the substrate  720 . As shown, the recessed surface  734  is generally defined by an inverted half rectangular shape. More specifically, the recessed surface  734  is defined by three surface portions: 1) a first linear surface  740  is recessed from the first interior surface  735  in accordance with the inverted half rectangular shape, 2) a second linear surface  742  is recessed from the second interior surface  737  and parallel to the first linear surface  740  in accordance with the inverted half rectangular shape, and 3) a third linear surface  738  is attached and perpendicular to both the first and second linear surfaces  740 ,  742  in accordance with the inverted half rectangular shape. Alternatively, the inverted conical shaped grooves of FIGS. 2 and 5 or the inverted half circular grooves of FIG. 4 can be incorporated in the elongated members  722 ,  758  of the substrate  720  shown in FIG. 7.  
         [0052]    As shown, the recessed surfaces  734  of the associated elongate members  722 ,  758  are substantially the same dimension. Likewise, as shown, the exterior surfaces  730  of the associated elongate members  722 ,  758  are substantially the same dimension. Accordingly, as shown, the associated elongate members  722 ,  758  are generally symmetrical. Alternatively, the grooves  724  of the elongate members  722 ,  758  can have different dimensions, different shapes, or any combination thereof, creating numerous additional embodiments of the invention. Additionally, the overall half cylindrical shape of an elongate member can be varied. For example, the cross-section of the overall shape can be half oval, triangular, square, rectangular, half pentagonal, half hexagonal, half octagonal, etc. Still further alternatives include substrates made from two elongate members with different cross-sectional shapes and/or different groove shapes.  
         [0053]    Referring to FIG. 8, geometric views of a substrate for a fiber optic device in another embodiment of the invention is provided. An isometric view and a cross-sectional view of the substrate  820  is shown. The substrate  820  is comprised of four elongate members  822 ,  858 ,  859 ,  860 . Each elongate member (e.g.,  822 ) has two mating surfaces facing adjacent elongate members (e.g.,  858 ,  860 ) and an interior surface facing an opposite elongate member (e.g.,  859 ). There is a groove  824  in the interior surface of the elongate member  822 . The groove  824  is substantially parallel to a longitudinal axis of the elongate member  822 . For alignment, the mating surfaces may also include nubs and corresponding slots in the mating surface of the adjacent elongate member, slots and corresponding nubs in the mating surface of the adjacent elongate member, ridges and corresponding grooves in the mating surface of the adjacent elongate member, grooves and corresponding ridges in the mating surface of the adjacent elongate member, other types of suitable alignment features, or any combination thereof  
         [0054]    The elongate member  822  has a generally quarter octagonal cross-sectional shape with the octagonal shape quartered at approximately the mid-point of alternating octagonal sections. The elongate member  822  is defined by an elongate surface  826  and two ends  828 ,  829 . The elongate surface  826  is further defined by the generally quarter octagonal shape of the elongate member  822  and the groove  824 . The elongate surface  826  is still further defined by two surface portions: 1) an exterior surface and 2) an interior surface. The exterior surface is defined by the generally quarter octagonal shape of the elongate member  822  and includes a first exterior portion  830  relating to half of an octagonal section, a second exterior portion  832  relating to an octagonal section, and a third exterior portion  831  relating to half of an octagonal section. The interior surface is defined by a first mating surface  835  facing a first adjacent elongate member, a second mating surface  837  facing a second adjacent elongate member, first and second interior surfaces  841 ,  843  generally parallel to the second exterior surface  832  and facing an opposite elongate member, and 4) a recessed surface  834  defined by the shape of the groove  824 .  
         [0055]    The recessed surface  834  is further described in reference to the cross-sectional view of the substrate  820 . As shown, the recessed surface  834  is generally defined by an inverted half rectangular shape. More specifically, the recessed surface  834  is defined by three surface portions: 1) a first linear surface  840  is recessed from the first interior surface  835  in accordance with the inverted half rectangular shape, 2) a second linear surface  842  is recessed from the second interior surface  837  and parallel to the first linear surface  840  in accordance with the inverted half rectangular shape, and 3) a third linear surface  838  is attached and perpendicular to both the first and second linear surfaces  840 ,  842  in accordance with the inverted half rectangular shape. Alternatively, the inverted conical shaped grooves of FIGS. 2 and 5 or the inverted half circular grooves of FIG. 4 can be incorporated in the elongated members  822 ,  858 ,  859 ,  860  of the substrate  820  shown in FIG. 8.  
         [0056]    As shown, the recessed surfaces  834  of the associated elongate members  822 ,  858 ,  859 ,  860  are substantially the same dimension. Likewise, as shown, the exterior surfaces  830  and interior surfaces  835 ,  837 ,  841 ,  843  of the associated elongate members  822 ,  858 ,  859 ,  860  are substantially the same dimension. Accordingly, as shown, the associated elongate members  822 ,  858 ,  859 ,  860  are generally symmetrical. Alternatively, the grooves  824  of the elongate members  822 ,  858 ,  859 ,  860  can have different dimensions, different shapes, or any combination thereof, creating numerous additional embodiments of the invention Additionally, the method of quartering the octagonal cross-section can be varied so that the exterior surface includes two full octagonal sections instead of quartering the sections at approximately the mid-point of alternating sections. Of course, the method of quartering the octagonal cross-section can also be varied by quartering the octagonal sections at any point in alternating sections as long as each quadrant is quartered in relatively the same manner. This alternative would produce non-symmetrical elongate members.  
         [0057]    Additionally, the overall shape of an elongate member can be varied. For example, the cross-section of the overall shape can be quarter circle, quarter square, quarter rectangular, quarter oval, etc. Still further alternatives include substrates made from two elongate members with different cross-sectional shapes and/or different groove shapes.  
         [0058]    Referring to FIGS. 7 and 8, the substrates  720  and  820  can be made from glass, silicon, sapphire, ceramic, or other suitable materials. Preferably, glass (e.g, Clear-Strate™ fused quartz by Quality Quartz of America, Inc.), generically known as vitreous silica, is used to make the substrate. The substrate can be formed by machining, extruding, or other suitable methods The length  244  of the substrate  720 ,  820  can range from 5 mm to 100 mm with a typical tolerance of +/−0.25 mm. The outside diameter  246  of the substrate  720  can range from 1 mm to 5 mm with a typical tolerance of +/−0. 10 mm. The exterior width  846  of the substrate  820  can range from 1.5 mm to 6 mm with a typical tolerance of +/−0.10 mm. The width  248  of the groove may have a typical tolerance of +/−0.10 mm. The depth  252  of the groove may have a typical tolerance of +/−0.10 mm. Alternate dimensions and tolerances, suitable for use in fiber optic devices, will be clear to those skilled in the art upon reading this disclosure. Such alternate dimensions and tolerances are considered within the scope of this disclosure and the attached claims.  
         [0059]    Referring to FIG. 9, geometric views and a cross-sectional view of a fiber optic device using the substrate in the embodiment shown in FIG. 7 are provided. Similar to the fiber optic device  610  of FIG. 6, the fiber optic device  910  is comprised of two fiber optic input cables  612 , four fiber optic output cables  614 , and a substrate  920 . As shown, the substrate  920  is like the substrate  720  described above in reference to FIG. 7 and made from, for example, Clear-Strate™ fused quartz. However, the substrate  920  can include more than two elongate members  922 ,  958  (e.g., three elongate members, substrate  820  with four elongate members, etc.), the cross-sections of the substrate  920  can be in various other shapes (e.g., oval, triangular, square, rectangular, pentagonal, hexagonal, octagonal ( see FIG. 8), etc.), and the grooves can have a cross-section in various other shapes (e g., substrate  220 ,  420 ,  520 , and others, as described above). The fiber optic cables  612 ,  614  are as described above in reference to FIG. 6. The substrate  920  includes two elongate members  922 ,  958 . Each elongate member (e.g.,  922 ) includes an optically isolated groove  924 . Like the fiber optic device  610  of FIG. 6, each groove  924  receives one fiber optic input cable  612  and two fiber optic output cables  614 . The fiber jacket  616  of each fiber optic cable  612 ,  614  is disposed in an end portion of the groove  924  and may be secured in position with an epoxy  621  or equivalent adhesive. Like in FIG. 6, the epoxy  621  or equivalent adhesive provides a form of strain relief to the fiber optic cable  612 ,  614  and a form of protection to the interior connections of the optical fibers  615 . The optical fiber  615  of each fiber optic cable  612 ,  614  is disposed in a connection region  954  of the groove  924  and may be secured in position with a suitable adhesive  923  or an equivalent material compatible with the materials of the optical fiber  615  and the substrate  920 . Like in FIG. 6, the adhesive  623  or equivalent material provides support for the optical fibers  615 .  
         [0060]    As shown, the optical fibers  615  from one fiber optic input cable  612  and two fiber optic output cables  614  in the connection region  954  of the first elongate member  922  are connected to each other forming a first coupling. The optical fibers  615  from the one fiber optic input cable  612  and the two fiber optic output cables  614  in the connection region  954  of the second elongate member  958  are connected to each other forming a second coupling. The substrate  920  and the connection ends  618  of the fiber optic cables  612 ,  614  are packaged in an enclosure  927 . The enclosure  927  may be adapted for use with strain relief boots  956 ,  957  on each end of the enclosure  927  Openings in the strain relief boots  956 ,  957  receive the fiber optic cables  612 ,  614  and provide strain relief to protect the interior connections of the optical fibers  615 .  
         [0061]    Like the fiber optic device  610  of FIG. 6, the fiber optic device  910  of FIG. 9 may be assembled using four fiber optic cables. A length of the fiber jacket  616  is removed from a middle portion of each cable to expose the optical fiber  615 . The optically isolated groove  624  in the first elongate member  922  receives two of the fiber optic cables such that the exposed optical fibers  615  are disposed in the connection region  954  The two exposed optical fibers  615  are connected together in the connection region  954  forming a first coupling with four fiber optic cables, each cable having a connection end  617  connected together to form the first coupling and a lead end  618  extending outward from the first coupling. One of the fiber optic cables is selected and severed from the first coupling leaving the lead ends  618  of one fiber optic input cable  612  and two fiber optic output cables  614  extending from opposing ends of the optically isolated groove  924  in the first elongate member  922 . The optically isolated groove  924  in the second elongate member  958  receives the other two fiber optic cables such that the exposed optical fibers  615  are disposed in the connection region  954 . These two exposed optical fibers  615  are connected together in the connection region  954  forming a second coupling with four fiber optic cables, each cable having a connection end  617  connected together to form the second coupling and a lead end  618  extending outward from the second coupling. One of the fiber optic cables is selected and severed from the second coupling leaving the lead ends  618  of one fiber optic input cable  612  and two fiber optic output cables  614  extending from opposing ends of the optically isolated groove  624  of the second elongate member  958 . The substrate  920  and the couplings are packaged in the enclosure  927 .  
         [0062]    As described, the fiber optic device  910  of FIG. 9 is a fiber optic coupler assembly with two optically isolated couplings. As shown, both couplings are commonly known as 1×2 dividers. Alternatively, simply by reversing the input and output ports, in other words defining item  612  as fiber optic output cables and item  614  as fiber optic input cables, both couplings are commonly known as 2×1 combiners. In alternate configurations, the fiber optic device can have multiple input ports (e.g., 1 to 64) and multiple output ports (e.g., 1 to 64) for each optically isolated coupling.  
         [0063]    In still further alternative configurations, the fiber optic device  910  can include one or more additional components (e.g., waveguides and/or semiconductor devices) and each of the optical fibers  615  can be connected to a predetermined point on the additional component(s). These alternate configurations are examples of using the substrate  920  made from, for example, Clear-Strate™ fused quartz in optical switches, wavelength-division multiplexers, and optical repeaters. The additional component(s) are disposed in the connection regions  954  of at least one of the optically isolated grooves  924  of the substrate  920 . Assuming at least one additional component is disposed in each of the grooves  924 , the fiber optic device  910  of FIG. 9 may be assembled using four or more fiber optic cables. A length of the fiber jacket  616  is removed from a connection end  617  of each cable to expose the optical fiber  615 . The optically isolated groove  924  in the first elongate member  922  receives at least two fiber optic cables such that the connection ends  617  are disposed in the connection region  954 . The connection ends  617  are connected to predetermined points on the additional component(s) with the lead ends  618  extending outward from the substrate  920 . The optically isolated groove  924  in the second elongate member  958  also receives at least two fiber optic cables such that the connection ends  617  are disposed in the connection region  954 . The connection ends  617  are connected to predetermined points on the additional component(s) with the lead ends  618  extending outward from the substrate  920 . The substrate  920  and additional component(s) are packaged in the enclosure  927 .  
         [0064]    While the invention is described herein in conjunction with exemplary embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the embodiments of the invention in the preceding description are intended to be illustrative, rather than limiting, of the spirit and scope of the invention. More specifically, it is intended that the invention embrace all alternatives, modifications, and variations of the exemplary embodiments described herein that fall within the spirit and scope of the appended claims or the equivalents thereof.