Abstract:
This disclosure teaches an optical transposer that provides “passive” alignment between optical waveguides in a silicon photonics die seated within a receptacle that is formed in a body member of the optical transposer and corresponding optical waveguides that are precisely dimensioned and located within the body member via laser scribing. The manufacturing method and optical transposer configuration taught herein allow for essentially automated placement (e.g., seating and gluing) of silicon photonics dies within corresponding optical transposer receptacles, without need for controlling final die alignment/placement as a function of measured optical insertion loss. In particular, such passive alignment is obtained via accurate dimensioning of the receptacles relative to the dies and by precise positioning of the entry points into the receptacles of the optical waveguides that are laser scribed into the body member of the optical transposer.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to optical waveguides and coupling, and particularly relates to coupling to an optical waveguide in a silicon photonics die. 
       BACKGROUND OF THE INVENTION 
       [0002]    In a silicon photonic circuit, the silicon serves as the optical medium. For example, an optical waveguide may be formed in a silicon layer and light may be confined to the optical waveguide by cladding the silicon material on its top and bottom with silicon dioxide (SiO2), for example. 
         [0003]      FIG. 1  illustrates an example silicon photonics die  10  (“die  10 ”). The die  10  has an exterior die edge  12  along a vertical face of the die  10 , which includes an optical waveguide  14 . The centerline or optimal alignment point for the optical waveguide  14  is denoted by line  16 , and is also referred to as the (X 2 , Z 2 ) point within the X, Y, Z dimensional references of the die  10 . Merely as an example configuration for discussion, the die  10  may have electrical contacts—not shown—for converting input electrical signals into corresponding light emissions transmitted through the optical waveguide  14 , or for converting light coupled into the optical waveguide into corresponding output electrical signals. 
         [0004]    Transmitting or receiving light through the optical waveguide generally requires precise alignment of an optical fiber or other external optical coupling medium or element with the optical waveguide  14 . In this regard, the critical alignment point of the optical waveguide  14  may be referred to as the (X 2 , Z 2 ) point, where the die  10  has X, Y, and Z dimensions of (X 1 , Y 1 , Z 1 ). With this notation, it will be appreciated that (X 2 , Z 2 ) defines a point within the die face running along the exterior edge  12  of the die  10 . It is known to manufacture such dies with X 1 , Y 1 , and Z 1  dimensions in the range of 100-250 μm. In turn, the cross-sectional dimensions of single-mode silicon waveguide is in the range of a few hundred nanometers. Of course, these dimensions should be understood as non-limiting examples. 
         [0005]    With such small dimensions involved, coupling to the die  10  in a manner that achieves and maintains accurate optical alignment with the die&#39;s waveguide(s) is difficult. It is known to use hetero-structure like grating couplers or butt coupling at the edge  12  of the die  10 , but such usage does not overcome the problems that are inherent in fixing the alignment of a single-mode optical fiber having a minimum diameter of typically 8000 nm or 9000 nm to the (X 2 , Z 2 ) optical alignment point of the optical waveguide  14 . 
         [0006]    Indeed, “active” alignment is a known technique for obtaining acceptable insertion loss between the optical waveguide  14  and an optical fiber coupled to it. In manufacturing processes based on active alignment, the alignment process is controlled according to live or ongoing direct or indirect measurements of insertion loss. Such approaches can be understood as a “closed loop” approach in which observations of optical and/or electrical measurements drive the mechanical alignment between the optical waveguide  14  and an external coupler, such as a single-mode optical fiber. 
         [0007]    However, while active alignment can be used to obtain sufficiently accurate alignment between external couplers and corresponding optical waveguides  14  in dies  10 , active alignment has several disadvantages. For example, active alignment can be time consuming, depending of course upon the sophistication of the manufacturing system(s) used to vary and fix the alignment and to measure insertion loss or other alignment parameters, for error signal feedback into the alignment process. Further, active alignment systems can be expensive, particularly if they are designed for high-speed/high-volume coupling operations. 
       SUMMARY 
       [0008]    This disclosure teaches an optical transposer that provides “passive” alignment between optical waveguides in a silicon photonics die seated within a receptacle that is formed in a body member of the optical transposer and corresponding optical waveguides that are precisely dimensioned and located within the body member via laser scribing. The manufacturing method and optical transposer configuration taught herein allow for essentially automated placement (e.g., seating and gluing) of silicon photonics dies within corresponding optical transposer receptacles, without need for controlling final die alignment/placement as a function of measured optical insertion loss. In particular, such passive alignment is obtained via accurate dimensioning of the receptacles relative to the dies and by precise positioning of the entry points into the receptacles of the optical waveguides that are laser scribed into the body member of the optical transposer. 
         [0009]    In an example embodiment, the contemplated optical transposer comprises a body member that is configured as a carrier for a silicon photonics die that has an optical waveguide positioned along a die edge. The body member includes a laser-scribed optical waveguide that opens into an interior face of a receptacle that is formed within the body member. The receptacle is dimensioned to receive and passively align the optical waveguide of the silicon photonics die with the optical waveguide of the optical transposer. 
         [0010]    In a corresponding example, the contemplated manufacturing method includes forming a receptacle within a body member of an optical transposer. The forming operation includes dimensioning the receptacle to receive a silicon photonics die in optical alignment with an optical waveguide of the optical transposer, which opens into an interior face of the receptacle. That is, the optical waveguide of the optical transposer is fabricated so that one end of it opens into the receptacle at a location that aligns with the optical waveguide of the silicon photonics die, when the die is seated in the receptacle. Laser scribing is used to form at least a portion of the optical waveguide of the optical transposer into the body member, to achieve precise dimensioning and position and/or to reduce manufacturing time and expense. 
         [0011]    Of course, the present invention is not limited to the above features and advantages. Indeed, those skilled in the art will recognize additional features and advantages upon reading the following detailed description of example embodiments, and upon viewing the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a diagram of a known silicon photonics die arrangement, illustrating an optical waveguide along an exterior edge of the die. 
           [0013]      FIG. 2  is a diagram of one embodiment of an optical transposer as taught herein, which advantageously serves as a carrier for a silicon photonics die and provides passive alignment between the optical waveguides in the die and the optical waveguides in the optical transposer, which are precisely positioned and dimensioned within a body member of the optical transposer using laser scribing. 
           [0014]      FIG. 3  is a logic flow diagram of one method of manufacturing an optical transposer, as contemplated herein. 
           [0015]      FIG. 4  is a diagram of other embodiments of the optical transposer, as used in context with a modular circuit assembly. 
           [0016]      FIG. 5  is a diagram of example details for changing a pitch (spacing) of optical interconnects using an embodiment of the optical transposer contemplated herein. 
           [0017]      FIGS. 6A and 6B  are diagrams of further example details, wherein electrical contacts are integrated into a receptacle of an optical transposer, for electrically contacting corresponding electrical contacts of a silicon photonics die. 
           [0018]      FIG. 7  is a diagram of further example manufacturing details for an optical waveguide feature that is at least partially formed in an optical transposer via laser scribing. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]      FIG. 2  depicts one embodiment of an optical transposer  20 , as contemplated herein. The term “transposer” will be understood as denoting a carrier for one or more silicon photonics dies  10  (“die  10 ” or “dies  10 ”), wherein that carrier has the properties, features, and advantages detailed by way of example herein. 
         [0020]    In the illustrated example, the die  10  has body dimensions of X 1 , Y 1 , and Z 1 , and has multiple optical waveguides  14 , e.g.,  14 - 1 ,  14 - 2 , and so on, which are exposed within an exterior face running along the edge  12  of the die  10 . The reference number “ 14 ” will be used in the singular and plural senses without any suffixing, unless suffixes aid clarity. 
         [0021]    The optical transposer  20  in the illustrated example comprises a body member  22  that is configured as a carrier for the die  10 , which, as noted, has a number of optical waveguides  14  positioned along a die edge  12 . The body member  22  includes a set  26  of laser-scribed optical waveguides  28  opening into an interior face  34  of a receptacle  24  that is formed within the body member  22 . The receptacle  24  is dimensioned to receive the die  10  into a seated position within the receptacle  24  and thereby passively align each optical waveguide  14  of the die  10  with a corresponding one of the optical waveguides  28 , which are formed into the body member  22  of the optical transposer  20  and which open into the receptacle  24  at precisely located points corresponding to the locations of the optical waveguides  14  of the die  10  in its seated position. 
         [0022]    In at least some embodiments, the body member  22  is a silicon-based glass material and the optical waveguides  28  are formed within that material. By way of non-limiting example, in at least one such embodiment the body member  22  is made from one of: Silicon Oxinitride (SiO x N y ), Germanium Dioxide (GeO 2 ), or doped Silicon Dioxide (SiO 2 ). 
         [0023]    In any case, the body member  22  is made of a material possessing suitable physical, thermal, optical and electrical properties. In particular, the body member material should provide for precise machining, molding, or other formation of the receptacle  24 , to provide for precise matching with the X 1 , Y 1 , Z 1  dimensions of the die  10 . That is, the corresponding X 3 , Y 3 , Z 3  dimensions of the receptacle  24  are sized to provide a precise seating of the die  10  within the receptacle  24 , so that each optical waveguide  14  of the die  10  passively aligns with a corresponding optical waveguide  28  of the optical transposer  20 , when the die  10  is seated within the receptacle  24 . 
         [0024]    For example, in one embodiment, the nominal X 3 , Y 3  and Z 3  dimensions of the receptacle  24  are set a few percent larger than the nominal X 1 , Y 1 , Z 1  dimensions of the die  10 . It is also contemplated to make allowances, e.g., in the X 3  and/or Z 3  dimensions, to accommodate bonding material, such as a thin layer of low-viscosity glue. Of course, other variations are contemplated. For example, the Z 3  dimension can be appreciably larger than the maximum Z 1  dimension of the die  10 —i.e., the receptacle  24  can be deeper than the die  10  is tall—and a lid or other retaining element can be fixed into place over the receptacle  24 , to hold the die  10  in position within the receptacle  24 . Similarly, the Y 3  dimension can be appreciably larger than the Y 1  dimension, thus allowing the die  10  to be slid into or otherwise seated all the way forward into the receptacle  24 , with a back-end retainer or bonding material used within the open receptacle space afforded by the Y 3 −Y 1  difference. 
         [0025]    Moreover, the coefficient of thermal expansion and/or other thermal properties of the optical transposer  20  should be suitable for the contemplated application. Preferably, the optical transposer  20  will be made from a material that is relatively insensitive to temperature, in terms of thermal expansion, and the material will be relatively well matched to the thermal expansion characteristics of the die  10 . 
         [0026]    A key aspect is that the body member  22  includes one or more optical waveguides  28  formed therein. Each optical waveguide  28  opens into the receptacle  24  and precisely aligns with a corresponding optical waveguide  14  of the die  10 , when the die  10  is seated in the receptacle  24 . A laser-scribing process is used to precisely form at least a portion of each optical waveguide  28 , to insure precision alignment with the corresponding optical waveguide  14  of the die  10 . 
         [0027]    Laser scribing is cheaper and more efficient than the active alignment mentioned in earlier herein. On the other hand, while laser scribing is more time consuming and expensive than photolithography etching for large volume manufacturing, it offers the precision of active alignment at lower cost and with more flexibility, including post-processing. One aspect of such flexibility flows from the fact that optical transposer  20  can be understood as decoupling the die  10  from the details of final fiber or other interconnect coupling. Further, laser scribing allows for the formation of waveguide structures in bulk material, which would not be possible with etching. 
         [0028]    For example, laser scribing can be used to form the terminal portion of each optical waveguide  28  where it opens into the receptacle  24 , for precise alignment. In another example, laser scribing is used to form longer portions of an overall optical waveguide  28  within the body member  22 , e.g., to save manufacturing time and because laser scribing allows precision at the junction between a preformed section of optical waveguide  28  and a laser-scribed portion of the same optical waveguide  28 . 
         [0029]    In the example of  FIG. 2 , one can see that the die  10  has four optical waveguides  14 - 1 ,  14 - 2 ,  14 - 3  and  14 - 4 . Correspondingly, the body member  22  of the optical transposer  20  includes a set  26  of four optical waveguides  28 . Each optical waveguide  28  includes a first end  30  and a second end  32 . That is, a first one of the optical waveguides  28  has opposing ends  30 - 1  and  32 - 1 , a second one of the optical waveguides  28  has opposing ends  30 - 2  and  32 - 2 , and so on. 
         [0030]    The first end  30  of each optical waveguide  28  opens into an interior face  34  of the receptacle  24  at a location that aligns with a corresponding one of the optical waveguides  14  of the die  10 , when the die  10  is seated in the receptacle  24 . That is, each first end  30  is located at a position (X 4 , Z 4 ) on the interior face  34  of the receptacle  24  that precisely aligns with a corresponding one of the optical waveguides  14  of the die  10 , when the die  10  is properly seated within the receptacle  24 . 
         [0031]    Accurate alignment between the first ends  30  of the optical waveguides  28  and respective ones of the optical waveguides  14  in a seated die  10  is obtained in at least some embodiments by laser-scribing of the first end  30  of each optical waveguide  28  within the interior face  34  of the receptacle  24  and by accurate dimensioning of the receptacle  24 . This arrangement “automatically” yields sufficiently precise optical alignment between the optical waveguides  14  of the die  10  and the corresponding first ends  30  of the optical waveguides  28  of the optical transposer  20 , upon proper seating of the die  10  within the receptacle  24 . 
         [0032]    Here, “proper seating” means that the die  10  is seated within the receptacle  24  so that its edgewise face along the exterior edge  12  (which face carries the optical waveguides  14 ) engages with or otherwise abuts the interior face  34  of the receptacle  24 , which includes the first ends  30  of the optical waveguides  28 . Equivalently, it is contemplated that the die  10  may have additional or alternative exit points for its optical waveguides  14  on its bottom surface relative to the receptacle  24 . In such a case, the optical waveguides  28  of the optical transposer  20  are formed in corresponding positions in the seating surface of the receptacle  24 . Thus, the terms “edge” and “face” as used herein to refer to the die  10  and the body member  22  should be given a broad construction, and may be referring to any surface of the die  10  and any corresponding engaging surface in the receptacle  24 , where such surfaces may be horizontal, vertical, etc. 
         [0033]    Continuing with the example of  FIG. 2 , the second end  32  of each optical waveguide  28  of the transposer  20  opens into an exterior face  36  along an exterior edge  38  of the body member  22 . In an advantageous but non-limiting example embodiment, each such second end  32  is configured to receive an optical fiber. Such an arrangement provides convenient termination of an optical fiber at the second end  32  of each optical waveguide  28 . An optical fiber is thus placed into alignment with an optical waveguide  14  of the die  10  by virtue of connecting it to the terminal end  32  of a respective one of the optical waveguides  28  of the optical transposer  20 . 
         [0034]    In one or more embodiments, the die  10  includes a plurality of optical waveguides  14  along a die edge  12 , and the body member  22  of the optical transposer  20  includes a plurality of optical waveguides  28 , each opening into the interior face  34  of the receptacle  24 . Each such optical waveguide  28  aligns with a respective one of the optical waveguides  14  of the die  10 , when the die  10  is seated within the receptacle  24 . 
         [0035]    As a further option, the optical transposer  20  may be used to change the pitch or geometry used for optically coupling with the plurality of optical waveguides  14  of the die  10 . For example, the first ends  30  of the plurality of optical waveguides  28  formed in the body member  22  open into the receptacle  24  at a first spacing—which spacing is dictated by the spacing of the optical waveguides  14  of the die  10 . However, the second ends  32  of the plurality of optical waveguides  28  formed in the body member  22  open into a second receptacle  24  (not shown in  FIG. 2 ) in the body member  22 , or into an exterior face  36  of the body member  22 , at a second spacing that is greater than the first spacing. Of course, it should be understood that other relationships can be configured between the first spacing and the second spacing. 
         [0036]    Equivalently, the geometry, arrangement, and/or order of the second ends  32  may differ from that of the first ends  30 , which must be arranged according to the arrangement of optical waveguides  14  in the die  10 . Those skilled in the art will appreciate the potential advantages gained by expanding the pitch and/or geometry between the second ends  32 , as compared to that used for the first ends  30 , in terms of simplifying connections to external couplers, such as multiple optical fibers, etc. In an example arrangement, the second ends  32  are arranged in a geometry corresponding to a multi-core fiber, to thereby transmit or receive differing optical signals on different fiber cores to or from different ones of the optical waveguides  14  in the die  10 . 
         [0037]    With the above in mind,  FIG. 3  illustrates an example method  300  of manufacturing the contemplated optical transposer  20 . The method  300  includes forming the (die) receptacle  24  in the body member  22  (Block  302 ). In an example case, the receptacle  24  is machined into the body member  22 . However formed, key manufacturing control variable inputs to this step include, e.g., the nominal die dimensions (X 1 , Y 1 , Z 1 ). The position (X 2 , Z 2 ) of each optical waveguide  14  provided by the die  10  also may be provided as an input. 
         [0038]    As noted before, the receptacle  24  may be formed or otherwise constructed to include certain additional features, such as die and/or alignment retaining features, and adhesive control features such as dams or drainage channels. For example, the floor of the receptacle  24  may be finely grooved to permit the outflow of excess glue, to prevent the die  10  from floating on a layer of adhesive and becoming vertically misaligned relative to the optical waveguide(s)  28  in the interior face  34  of the receptacle  24  during the die seating process. 
         [0039]    The method  300  further includes a laser-scribing process, to form all or part of the optical waveguides  28  in the body member  22  (Block  304 ). In particular, in at least one embodiment, laser scribing is used to precisely locate the first end  30  of each optical waveguide  28  within the interior face  34  of the receptacle  24 . Thus, the critical alignment point of each optical waveguide  14 , as projected onto the interior face  34  of the die  10  when it is seated in the receptacle  34 , is provided as an input to this process. 
         [0040]    These points are denoted as the (X 4 , Z 4 ) locations and they represent the locations at which the first ends  30  of the optical waveguides  28  will be laser scribed into the interior face  34  of the receptacle  24 . Each (X 4 , Z 4 ) position can be determined, within applicable manufacturing tolerances, from the (X 2 , Z 2 ) location known for each optical waveguide  14  provided by the die  14 , along with a delta Z value associated with glue, etc., bearing on the final seated height of the die  10 . 
         [0041]    The method  300  may further include seating and/or gluing of the die  10  into the receptacle  24  (Block  306 ). However, these operations are not necessarily part of the contemplated method  300 , as optical transposers  20  may be made in advance, for a specific type/style of die  10 , and sold separately to a downstream manufacturer or module fabricator who provides the dies  10  and performs the die seating operation, e.g., as part of fabricating a larger assembly. In this regard, different models and configurations of optical transposers  20  are contemplated, for a range of die types, sizes, and configurations. It is also contemplated to provide different coupling solutions via different models of optical transposers  20 . For example, some models may be tailored for termination of optical fibers, while others may target System-on-a-chip or multi-chip module applications. Still others may provide a hybrid of these two targeted applications. 
         [0042]      FIG. 4  illustrates examples of such variations of the optical transposer  20 . In particular, one sees a multi-chip module substrate  40  carrying a pair of integrated circuits  42 - 1  and  42 - 2 . A first optical transposer  20 - 1  provides an electro-optical interface between the two integrated circuits  42  by providing a first receptacle  24 - 1  that provides electrical connections (not visible in the diagram) to the first integrated circuit  42 - 1  and provides optical coupling to a second receptacle  24 - 2  via a set  26  of waveguides  28 . 
         [0043]    Thus, in at least one embodiment, the optical transposer  20  further includes a second receptacle  24  formed within the body member  22  and dimensioned to receive a die  10  having one or more second optical waveguides  14  positioned along a die edge  12 . The optical waveguides  28  have their first ends  30  opening into the first receptacle  24  and their second ends opening into an interior face  34  of the second receptacle  24 , in alignment with the one or more second optical waveguides  14 . This arrangement thereby provides optical paths between the first optical waveguides  14  of the first die  10  and the second optical waveguides  14  of the second die  10 , when the dies  10  are seated in their respective first and second receptacles  24 . 
         [0044]    As a further example configuration, and as shown in the figure, the second receptacle  24 - 2  is optically coupled to a third receptacle  24 - 3  via another set  26  of waveguides  28 . Either or both of the second and third receptacles  24 - 2  and  24 - 3  may electrically couple to the second integrated circuit  42 - 2 , thus completing the bridging of the second integrated circuit  42 - 2  to the first integrated circuit  42 - 1 . The third receptacle  24 - 3  may further couple to a fourth receptacle  24 - 4  via yet another set  26  of waveguides  28 . 
         [0045]    Notably, the different receptacles  24  of the first optical transposer  20 - 1  may be configured for different types of dies  10 —i.e., one optical transposer  20  can carry more than one type of die  10 . A given receptacle  24  is “configured” for a particular type or style of die  10  by virtue of its (X 3 , Y 3 , Z 3 ) dimensioning and by the number and positioning of waveguides  28  opening into the receptacle  24 . 
         [0046]      FIG. 4  further depicts a second optical transposer  20 - 2  that includes two receptacles  24 - 5  and  24 - 6 , one or both of which include electrical interconnections for connecting to the second integrated circuit  42 - 2 . Moreover, the two receptacles  24 - 5  and  24 - 6  are optically coupled via a set  26  of waveguides  28 , and the receptacle  24 - 6  includes a further set of waveguides  28  whose second ends  32  open on an exterior face  36  of the optical transposer  20 - 2 . Advantageously, these second ends  32  are configured with fiber optic connectors  44  for terminating fiber optic cables  46 . 
         [0047]    It will be appreciated that the die  10  intended for the receptacle  24 - 6  includes optical waveguides  14  facing the optical waveguides  28  between the receptacle  24 - 6  and the receptacle  24 - 5 , and optical waveguides  14  facing the optical waveguides  28  that terminate on the exterior face  36  of the optical transposer  24 - 6 . Further, as illustrated in  FIG. 5 , the optical waveguides  28  that extend from the receptacle  24 - 6  to the exterior face  36  of the optical transposer  20 - 2  may change pitch from their first ends  30  to their second ends  32 . 
         [0048]    This arrangement allows, for example, changing from a pitch “P 1 ” between optical waveguides  14  on a die  10  to a pitch “P 2 ” between fiber optic connectors  44  or other external coupler arrangements adapted for termination on the exterior face  36  of the body member  22  of the optical transposer  20 - 2 . Of course, the ability to change pitch between respective ends of a set  26  of waveguides  28  may be used anywhere needed, e.g., to optically interconnect a first die  10  in a first receptacle  24  with a second die  10  in a second receptacle  24 , where the two dies  10  use different pitches between the two or more optical waveguides  14  provided by each die  10 . 
         [0049]    Similar flexibility may be used regarding electrical interconnections. As shown in  FIG. 6A , a given receptacle  24  may include electrical contacts  50  that are configured to engage corresponding electrical contacts  52  (shown in the die bottom view of  FIG. 6B ) of the silicon photonics die  10 , when the silicon photonics die  10  is seated within the receptacle  24 . The electrical contacts  50  in the receptacle  24  may extend through the body member  22 , e.g., for electrically contacting corresponding contacts on a substrate or other carrier on which the optical transposer  20  is mounted. Alternatively, the optical transposer  20  may be configured with a first set of electrical contacts for external connections, and those contacts may be wired or otherwise electrically coupled to the contacts  50  within the receptacle  24 . 
         [0050]    As a further point of manufacturing flexibility and/or efficiency, it is contemplated herein that laser-scribing be used for forming less than all of a given waveguide  28 . For example,  FIG. 7  depicts a top view of an example optical transposer  20 , wherein one or more portions  28 A of a waveguide  28  are fabricated using a manufacturing process other than laser scribing, e.g., a process that may be cheaper or simpler but perhaps less precise. In an example embodiment, the portion(s)  28 A are fabricated using photolithography. 
         [0051]    However, one or more key portions  28 B of the optical waveguide  28  are fabricated using laser scribing, to obtain the precise dimensioning available with that manufacturing process. In particular, a terminal portion of the optical waveguide  28  that ends in the first opening  30  into the receptacle  24  is laser scribed, to obtain the precise dimensioning and accurate positioning of that first opening  30  with respect to a corresponding optical waveguide  14  of a die  10 , when the die  10  is seated in the receptacle  14 . Similarly, the terminal portion of the optical waveguide  28  that ends in the second opening  32  also may be laser scribed. 
         [0052]    As for the laser scribing system used in forming all or portions of the optical waveguides  28 , commercial laser scribing systems are known. Further, as is known, the characteristics of the laser beam itself should be targeted to the particular material type used for the body member  22 . Selectable parameters for the laser include any one or more of: beam width, beam shape, laser wavelength, laser power, and laser pulse rate. The laser may be a diode-pumped solid-state (DPSS) laser, in which the pulse repetition rate, pulse width, laser wavelength, and beam power are tailored for micro-machining the type of material selected for the body member  22 . 
         [0053]    Use of laser scribing in the contemplated manner provides low cost, high-volume passive alignment of Si-photonics dies to other such dies and or to optical fibers or other external optical couplers. The laser scribing process offers this precision while at the same time being much simpler than other known technologies and laser scribing has no implicit thermal or polarization dependence. Also, as waveguides  28  can be laser-scribed in any direction on the body member  22  of the contemplated optical transposer  20 , it is contemplated herein to retrofit Si-photonics dies that use grating couplers, for example, to offer a superior coupling solution as compared to fiber-to-grating coupling, while obviating the need for new spin of the die. Such an approach has the potential to save significant money because it avoids the need for die redesign and a corresponding new CMOS (complementary metal oxide semiconductor) mask fabrication. 
         [0054]    Further, the optical transposer  20  offers great flexibility at the optical fiber interface point, and does so at a lower cost than spinning a different CMOS layout for different coupling patterns. Thus, the optical waveguides  14  of a given die  10  could come to the edge  12  of the die  10  and be coupled to the optical waveguides  28  of the optical transposer  20  in a parallel fashion and either keep the channels parallel or arrange them, e.g., in a desired multicore fiber pattern, or other pattern. 
         [0055]    Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.