Patent Publication Number: US-10775568-B2

Title: Single-mode polymer waveguide connector assembly device

Description:
BACKGROUND 
     Technical Field 
     The present invention relates to optical waveguides and, more particularly, to a single-mode polymer waveguide connector assembly device. 
     Description of the Related Art 
     Waveguides are used to transport, e.g., optical signals over large distances with very low losses. Waveguides employ, e.g., a difference between a refractive index for an internal medium called “core” and an external medium called “clad”. In the example of fiber optics, the transport medium “core” is made of a higher refractive index glass and the external medium “clad” is made of a lower refractive index glass. These two glass layers are surrounded by sheath, shielding, or air. When an optical signal in the inner core layer hits the boundary between core and clad, it is internally reflected instead of escaping from core layer. As a result, optical fibers can be used to transport very low-loss signals across long distances. 
     Optical fibers used for waveguides are thin, flexible, and frequently made of silica glass, but may also be made from, e.g., fluoride glass, phosphate glass, chalcogenide glass, or crystal materials such as sapphire. Appropriate materials are selected in accordance with desired refractive properties. Some fibers support many transverse transmission modes and are called multi-mode fibers, whereas others support a single mode and are called single-mode fibers. Single-mode fibers are frequently used for long-distance links, as multi-mode fibers are susceptible to modal dispersion over long distances due to slightly different transmission speeds between the different modes. 
     Polymer materials exhibit favorable properties for use in optical waveguides, which may be used for high-density optical interconnects in fiber-optic communications, optronics, and other light-based technologies. Waveguide connectors are used to connect between separate polymer waveguides and between polymer waveguides and glass fibers. 
     However, existing polymer waveguide connectors are difficult to install under precise positioning requirements. One such connector is the polymer mechanical transfer (PMT) connector which is used as a multimode polymer waveguide connector. These connectors are difficult to assemble with positioning errors of under a few micrometers and are simply not feasible for positioning errors of less than a micrometer. Positioning errors can lead to loss of signal from, e.g., reflections that occur at imperfect junctions. 
     In addition, contamination on the polymer waveguide connector effectively decreases adiabatic coupling between the polymer waveguide connector and a separate silicon waveguide, such as an optical circuit on a silicon (Si) chip. During Silicon photonic packaging, no overclad on the polymer waveguide connector is employed, and the polymer waveguide connector core and the silicon waveguide core are directly in contact with each for high efficient adiabatic coupling. Polyimide cover films and/or adhesive tape placed over the polymer waveguide connector core array to prevent contamination may cause tearing of the polymer waveguide connector and/or result in residual glue on the polymer waveguide connector when the polyimide cover film and/or adhesive tape is removed, thereby effecting efficiency of adiatic coupling between the polymer waveguide connector and silicon waveguide. 
     SUMMARY 
     A method for assembling a waveguide connector includes positioning a polymer waveguide in one or more insertion structures within an inner portion of a cap where the polymer waveguide has alignment features. The method also includes inserting a ferrule into the inner portion of the cap such that an inner wall of the cap seals around the assembled connector and heating the polymer waveguide and the ferrule to a first temperature with the ferrule comprising alignment features and having a different coefficient of thermal expansion from the polymer waveguide. The alignment features of the polymer waveguide align with the alignment features of the ferrule when the polymer waveguide and the ferrule are heated to the first temperature. 
     A method for assembling a waveguide connector includes applying glue to one or more insertion structures of a cap and inserting a polymer waveguide into the one or more insertion structures of the cap where the polymer waveguide includes alignment features. The method also includes inserting a ferrule into the inner portion of the cap such that an inner wall of the cap seals around the assembled connector and heating the polymer waveguide and the ferrule to a first temperature with the ferrule having alignment features and having a different coefficient of thermal expansion from the polymer waveguide. The alignment features of the polymer waveguide align with the alignment features of the ferrule when the polymer waveguide and the ferrule are heated to the first temperature. 
     A method for assembling a waveguide connector includes positioning a polymer waveguide in one or more insertion structures within an inner portion of a cap where the polymer waveguide includes alignment features and inserting a ferrule into the inner portion of the cap such that an inner wall of the cap seals around the assembled connector. The method also includes heating the polymer waveguide and the ferrule to a first temperature with the ferrule having alignment features and having a different coefficient of thermal expansion from the polymer waveguide, with the alignment features of the polymer waveguide aligning with the alignment features of the ferrule when the polymer waveguide and the ferrule are heated to the first temperature. The method also includes cooling the polymer waveguide and the ferrule to a second temperature such that tension is created within the material of the polymer waveguide due to the different contraction rate of the waveguide relative to the contraction rate of the ferrule and such that the tension pulls a plurality of cores of the waveguide into position. 
     These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a cross-sectional diagram of a waveguide connector assembly in accordance with the present principles; 
         FIG. 2  is a side view diagram of a waveguide connector assembly for photonic packaging in accordance with the present principles; 
         FIG. 3  is a perspective view diagram of a waveguide connector assembly device in accordance with the present principles; 
         FIG. 4  is a cross-sectional diagram of a waveguide connector assembly device in accordance with the present principles; 
         FIG. 5  is a cross-sectional diagram of a waveguide connector assembly device in accordance with the present principles; 
         FIG. 6  is a cross-sectional diagram of a waveguide connector assembly in accordance with the present principles; 
         FIG. 7  is a cross-sectional diagram of a waveguide connector assembly device in accordance with the present principles; 
         FIG. 8  is a cross-sectional diagram of a waveguide connector assembly in accordance with the present principles; 
         FIG. 9  is a perspective view diagram of a waveguide connector assembly device in accordance with the present principles; 
         FIG. 10  is a cross-sectional diagram of a waveguide connector assembly device in accordance with the present principles; and 
         FIG. 11  is a block/flow diagram of a method of forming a waveguide connector in accordance with the present principles. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention provide polymer waveguides with precise positioning, having positioning errors below one micrometer, and having a polymer waveguide core array with pristine surface areas for photonic packaging. To accomplish this, a polymer waveguide connector assembly device is provided. The polymer waveguide connector assembly device includes one or more guiding slots to receive a polymer waveguide chip and an enclosure to receive a glass lid, ferrule, and/or any other components of the polymer waveguide. The polymer waveguide connector assembly device may align the polymer waveguide chip, lid, ferrule, and/or any other components of the polymer waveguide while protecting the polymer waveguide chip from further processing steps to maintain a pristine surface on the polymer waveguide core array. 
     In some embodiments, the differing coefficients of thermal expansion (CTEs) of a waveguide material and a ferrule material are exploited by heating the two structures until they align, fastening the structures together, and letting them cool, thereby creating a tension in the polymer waveguide that precisely aligns the individual waveguides in the ferrule. By increasing the thickness of the bottom cladding of the polymer waveguide and by removing the backfilm that is normally used for support and positioning, the waveguide positioning may be made more consistent. 
     The functioning of a waveguide relies on total internal reflection of light—or other electromagnetic radiation—at a boundary. Waveguides at optical frequencies often take advantage of a difference in refractive index between two materials at the boundary. Fiber can be multi-mode or single-mode, referring to the propagation modes of the light as it passes through the waveguide. In the case of multi-mode fibers, multiple different transverse modes (i.e., multiple different light paths through the waveguide) can exist simultaneously in the relatively large waveguide core, where the core has a diameter that is much larger than the wavelength of the light carried. By contrast, in a single-mode fiber, only one transverse mode, called a zeroth mode or a fundamental mode, exists. This advantageously inhibits modal dispersion and provides superior fidelity of signals over long distances. In a single-mode fiber, a wavelength division multiplex (WDM) technology is often used for a broadband communication. When WDM is applied, multiple different frequencies of light are transmitted along one single-mode fiber, each propagating along the fiber in the fundamental mode. When dealing with single-mode optical fiber, an intuitive geometric interpretation for the propagation of light within the fiber is unavailable, with the behavior of the propagation being modeled instead using the Helmholtz equation. 
     Referring now to the drawings in which like numerals represent the same or similar elements and initially to  FIG. 1 , an exemplary polymer waveguide assembly  100  is illustratively depicted. In  FIG. 2 , the placement of a polymer waveguide  104  on a ferrule  102  is shown. The ferrule  102  may include a U-shaped structure. A lid  106  is used to place and hold the waveguide  104 . It is contemplated that the waveguide  104  may have an exemplary CTE of about 50 ppm/° C., while the ferrule  102  may have an exemplary CTE of about 1 ppm/° C. The waveguide  104  includes a set of waveguide cores  114 , a set of narrow grooves  111  between cores, and two wide grooves  110  on both sides of the core array. 
     The ferrule  102  includes two wide studs  112  and a set of narrow studs  116 . At room temperature (e.g., 25° C.), if the distance between the two grooves  110  is about 3 mm, this distance would be an exemplary 3 μm smaller than the distance between the two studs  112  at room temperature. At a temperature of 45° C., however, the differing CTEs of the two structures results in the grooves  110  aligning with the studs  112 , with the waveguide cores  114  also aligning with the narrow studs  116 . It is specifically contemplated that the ferrule  102  may be part of, e.g., a mechanical transfer (MT) connector, but any appropriate connector may be used instead. It should be noted that other configurations of the waveguide connector assembly  100  is readily contemplated, including additional materials, and the embodiment shown in  FIG. 1  is merely illustrative of a waveguide connector assembly in accordance with the present principles. 
     Optical connectors terminate an end of the optical fiber and provide for rapid connection and disconnection. By aligning the fibers of two sections of optical cable, the connectors ensure an easy connection and allow light to pass with little loss. Ideally the connectors have some form of locking ability that maintains a strong connection and prevents fibers in respective connectors from moving relative to one another. Maintaining good alignment is important for minimizing return loss, which occurs at discontinuities in the connection. Even small deviations in positioning and alignment can create significant return losses. The present embodiments bring cores  114  of respective connectors into alignment with very low deviation from the expected positions. 
     The MT connector is a multi-fiber connector that is often used for ribbon cables. It is used in, for example, predetermined cable assemblies and cabling systems. In particular, the MT connector allows multiple single-mode fibers to connected in parallel, such that one fiber ribbon cable will include multiple glass fibers and thereby provide increased transmission bandwidth. Connection strength is provided by latches on the connector that lock into place on a mated plug using a spring mechanism. Guide pins are used to aid in alignment of the ferrules  102  and removable housings may be employed for modularity. While this provides good mechanical alignment between two respective connectors, manufacturing imperfections can still result in misalignment between the small waveguide cores. 
     The polymer waveguide  104  is formed by forming waveguide cores on a lower refractive index under cladding polymer layer. The cores are formed by depositing, e.g., a higher refractive index polymer material using a photo lithography method or any other appropriate deposition method and patterning the core material to form waveguides of the desired shape. A lower index upper cladding polymer material is then deposited over the cores. The optical signal is confined by internal reflection to the waveguide core material at the interface between the waveguide core and the upper and lower cladding material. Single-mode glass fibers often have core diameters from about 5 to about 11 μm. The corresponding single-mode polymer waveguides also have a few cross sectional area of a few micrometers. 
     During placement, the waveguide  104  is heated to a temperature that causes an expansion of the waveguide  104 , allowing it to align with the studs  116  and  112  of the ferrule  102  as described above. A glue  108  is applied to respective grooves  110  of the waveguide  104  and studs  112  of the ferrule  102 . The glue  108  may be, e.g., an ultraviolet-cured glue that is then exposed to ultraviolet light, locking the sides of the waveguide  104  in place. Although it is specifically contemplated that a glue may be used, any other appropriate form of bonding may be employed instead. As the waveguide  104  cools, the waveguide  104  is prevented from shrinking accordingly and a tension is created within the waveguide  104  that pulls the polymer waveguide  104  flat and brings each waveguide core  114  into a precise position within the narrow studs  116 . 
     In some embodiments, a thickness of the waveguide  104  may be increased. The thicker waveguide  104  provides structure and consistency in CTE. A glass lid  106  is then applied directly to the waveguide  104  to apply pressure while the ultraviolet glue  108  sets. The thickness of the underclad portion of the waveguide  104  may be, for example, about 50 μm—increased relative to conventional waveguides which have the underclad portion with a thickness of about 20 μm. This thickness provides stability of a precise core position during assembly, easy manipulation of the waveguide  104 , and increased physical strength of the waveguide  104  after assembly. In one exemplary embodiment, the underclad portion of the waveguide  104  has a thickness of about 50 μm while the topclad portion that includes waveguide cores  114  has a thickness of about 23 to 24 μm. In this exemplary embodiment, a spacing between cores  114  is about 250 μm. 
     In some embodiments, omitting a back film and using a waveguide  104  provides superior alignment of the waveguide cores  114 , with experimentally demonstrated positioning errors of less than 1 μm. Improvements are shown in height, lateral, and absolute misalignment values. The thickness of the waveguide  104  does not decrease the CTE of the material, which is used to provide precise alignment of the waveguide cores  114 . 
     Referring now to  FIG. 2 , a cross-sectional side view of the polymer waveguide connector assembly for silicon photonic packaging is illustratively depicted. In  FIG. 2 , a portion of the waveguide  104  is disposed between the ferrule  102  and the lid  106 , while another portion of the waveguide  104  extends outwardly and connects to a silicon optical circuit on a silicon chip  200 . Specifically, the waveguide cores  114  on the waveguide  104  are aligned with and connect to respective silicon waveguides  202  on the silicon chip  200  via adiabatic coupling techniques. In some embodiments, alignment ridges and/or alignment grooves (not shown) on the waveguide  104  and/or silicon chip  200  may be employed for proper alignment of the waveguide cores  114  and silicon waveguides  202 . 
     Such connection between the waveguide  104  and the silicon chip  200  may enable a pitch conversion from the silicon chip  200  (e.g., 50 um) to the waveguide  104  (e.g., 250 um), and may experience lower loss connection than conventional connection methods, such as diffraction grating coupling. However, because the waveguide cores  114  and the silicon waveguides  202  are in direct contact with each other, the surface of the waveguide  104  at the interface between the waveguide  104  and the silicon chip  200  should be sufficiently clean and free of defects to employ efficient adiabatic coupling. 
     Now referring to  FIG. 3 , a perspective view of a polymer waveguide connector assembly device  300  is illustratively depicted. The assembly device  300  may include a cap  302 . The cap  302  may be formed of a transparent elastomer, transparent silicone, and/or a rubber material using an injection molding method (e.g., metal cast). In an embodiment, the cap  302  may include various dimensions and/or shapes suitable for receiving various components of the waveguide connector assembly  100 . While a cubic shape is illustratively depicted for the cap  302 , other shapes are readily contemplated. 
     In an embodiment, the assembly device  300  may include one or more insertion structures  304 , such as guiding slots, grooves, flanges, and/or tapered structures. The insertion structures  304  may extend from the cap  302 , such as an embedded structure, and/or may be integrally formed with the cap  302 . In some embodiments, the guiding slots may be formed of a transparent elastomer, transparent silicone, and/or a rubber material using an injection molding method (e.g., metal cast) as a part of the cap  302 . In some embodiments, the guiding slots may be formed of a hard polymer, such as acrylic, that may be added to an inner portion (e.g., inner wall) of the cap  302 . For example, the guilding slots may be added to the cap  302  as an independent component. The guiding slots may include various dimensions, such as 3 millimeters (mm) in length by 0.5 mm in width when using a waveguide  104  being 3 mm in width and 11 mm in length. For example, the insertion structures  304  may extend from a back inner wall or a ledge within the cap  302 . The insertion structures  304  may be configured to receive the waveguide  104  and maintain the position of the waveguide  104  during assembly of the waveguide connector assembly  100 . 
     In an embodiment, the insertion structures  304  may include grooves (not shown) having a thickness slightly larger than and/or substantially similar to a thickness of the waveguide  104 . For example, the waveguide  104  may fit within the grooves such that the grooves maintain proper positioning of the waveguide  104 . The grooves may be an indentation within the inner walls of the cap  302 . Accordingly, the insertion structures  304  may provide a contactless protector for the waveguide  104  and may provide slight tuning of the waveguide  104 . In an embodiment, the insertion structures  304  may include a spacing approximately between 10-100 um such that the waveguide  104  “sits” within the in the insertion structures  304  while the ferrule  102  is being aligned with the waveguide  104 . Accordingly, the insertion structures  304  may allow slight tuning (e.g., positioning) of the waveguide  104  in the X, Y, and/or Z directions. 
     The cap  302  may be employed to protect the waveguide  104  from contamination of polishing dusts and/or cleansing agents (e.g., washing liquids) during assembly of the waveguide connector assembly  100 . Accordingly, the present principles do not suffer from the effects of using polyimide cover films and/or adhesive tape placed over the waveguide  104 , such as tearing of the waveguide  104  and/or residual glue present on the waveguide  104 . 
     Referring to  FIG. 4 , a cross-sectional view of a polymer waveguide connector assembly device  400  is illustratively depicted. The waveguide  104  may be inserted into insertion structures  404 , such as flanges, attached/coupled to the cap  402 . In the embodiment shown in  FIG. 4 , the flanges  404  are positioned such that a top surface and a bottom surface of the waveguide  104  rests between the flanges  404 . A ferrule  102  and/or lid  106  may be inserted into an inner portion of the cap  402  having a height h such that the ferrule  102  is positioned under the waveguide  104  and the lid  106  is positioned over the waveguide  104 . The inner portion of the cap  402  conforms around the ferrule  102 , waveguide  104 , and/or lid  106  such that the inner portion of the cap  402  remains sealed, thereby protecting the waveguide  104  from contaminants. 
     In an embodiment, the ferrule  102  and the lid  106  may be inserted simultaneously subsequent to inserting the waveguide  104 . In an alternative embodiment, the ferrule  102  and the lid  106  may be inserted one after another. In an embodiment, the ferrule  102  and/or the lid  106  may be simultaneously or mutually inserted into the inner portion of the cap  402  prior to the insertion of the waveguide  104 . In an embodiment, the ferrule  102  may be inserted into the cap  402 , and waveguide  104  and/or lid  106  may be inserted through the ferrule  102 , which may be U-shaped, and aligned with the ferrule  102 . 
     The waveguide  104  may be heated to a temperature that causes an expansion of the waveguide  104 , allowing it to align with the studs  112 ,  116  (not shown) of the ferrule  102 , and a glue  108  (not shown), such as an ultraviolent glue and/or other bonding material, may be applied to respective grooves  110  (not shown) of the waveguide  104  and studs  112  of the ferrule  102 , as illustrated in  FIG. 1 . As the waveguide  104  cools, the waveguide  104  is prevented from shrinking accordingly and a tension is created within the waveguide  104  that pulls the polymer waveguide  104  flat and brings each waveguide core  114  (not shown) into a precise position within the narrow studs  116 . 
     In an embodiment, the polymer waveguide connector assembly device  400  may include a light source  406 . The light source  406  may propagate a lightwave through the cap  402  and travel traversely through the waveguide  104  and ferrule  102 . For example, the cap  402  may include transparent material configured to allow light from the light source  406  through the cap  402  and through the waveguide  104  and ferrule  102  to ensure proper alignment between the waveguide cores  114  (not shown) and narrow studs  116  (not shown). In an embodiment, the cap  402  may include a channel (not shown) to allow a lightwave to pass traversely through the cap  402 , waveguide  104  and ferrule  102 . 
     Referring now to  FIG. 5 , the ferrule  102 , waveguide  104 , and/or lid  106  may be polished and/or washed. For example, a polish may be employed using a polishing sheet and water, however it is readily contemplated that other polishing techniques are contemplated, such as employing a dry polishing sheet. In an embodiment, the ferrule  102 , waveguide  104 , and lid  106  may be polished at a specific angle, such as 8 degrees, however other angles are readily contemplated. 
     In a further embodiment, a washing process may be performed on the polymer waveguide connector assembly to remove any unwanted debris, such as polishing dusts and/or any other contaminants. Because the cap  402  surrounds and encloses the waveguide  104  during the polishing and/or washing processes, the cap prevents water, cleansing agents, polishing dusts, and further contaminants to enter, thereby protecting the waveguide  104  from any unwanted contaminants on the surface thereof. Accordingly, the surfaces of the waveguide  104  remain pristine for adiabatic coupling. The polymer waveguide connector assembly device  400  may be removed, and the polymer waveguide connector assembly  100  may be employed for further processing, including silicon photonic packaging. 
     Now referring to Referring to  FIG. 7 , a cross-sectional view of a polymer waveguide connector assembly device  700  is illustratively depicted. In an embodiment, the polymer waveguide connector assembly device  700  may include a cap  702  and one or more insertion structures  704 . The insertion structures  704  may include a tapered shape having a first thickness al which gradually thins and/or narrows towards one or more ends, such as an end at the opening of the cap  702  and/or an end toward the inner back wall of the cap  702 . The tapered structures  704  may firmly hold and position the waveguide  104 . The tapered structure  704  may be integrally formed with the cap  702  and/or may include the same materials employed for the cap  702 . For example, the tapered structure  704  may include materials such as a thermoplastic elastomer, thermosetting elastomer, silicone, and/or rubber. 
     A ferrule  102  and/or lid  106  may be inserted into an inner portion of the cap  702  such that the ferrule  102  is positioned under the waveguide  104  and the lid  106  is positioned over the waveguide  104 . The inner portion of the cap  702  conforms around the ferrule  102 , waveguide  104 , and/or lid  106  such that the inner portion of the cap  702  remains sealed, thereby protecting the waveguide  104  from contaminants. 
     Referring now to  FIG. 8 , another exemplary polymer waveguide assembly  800  is illustratively depicted. The ferrule  102  may include a U-shaped structure having one or more holes  806 . The holes  806  may extend through a portion of the ferrule  102  or through an entire width of the ferrule  102 . The holes  806  are shown as circular, however other shapes for the holes  806  are readily contemplated. While two holes  806  are shown, it is readily contemplated that additional holes  806  may be employed. A lid  106  is used to place and hold the waveguide  104  on the ferrule  102 . Additional features of the ferrule  102 , waveguide  104 , and/or lid  106  are described above with reference to  FIG. 1 . 
     Now referring to  FIG. 9 , with continued reference to  FIG. 1 , a perspective view of a polymer waveguide connector assembly device  900  in accordance with the present principles is illustratively depicted. The assembly device  900  may include a cap  902 , and may include various materials such as a transparent elastomer, transparent silicone, and/or a rubber material formed using an injection molding method. In an embodiment, the assembly device  900  may include one or more insertion structures  904 , such as guiding slots, grooves, and/or tapered structures. The insertion structures  904  may be configured to receive the waveguide  104  and maintain the position of the waveguide  104  during assembly of the waveguide connector assembly  100 ,  800 . 
     In an embodiment, the assembly device  900  may include one or more guide pins  906  extending from the cap  902 . The guide pins  906  may be formed from a stainless steel, however other materials are readily contemplated. In an embodiment, the guide pins  906  fit into the holes  806  of the polymer waveguide connector assembly  800  shown in  FIG. 8 . The guide pins  906  may help to align the ferrule  102  and waveguide  104  to ensure proper alignment of the waveguide cores  114  and studs  112 ,  116 . In an embodiment, guide pins  906  may extend from a back inner wall or a ledge within an inside wall of the cap  902 . 
     Now referring to  FIG. 10 , a cross-sectional view of the polymer waveguide connector assembly device  900  is illustratively depicted. The waveguide  104  may be inserted into insertion structures  904 , such as flanges, grooves, and/or tapered structures, attached/coupled to the cap  902 . The ferrule  102  may be inserted between the waveguide  104  and the cap  902 . In an embodiment, guide pins  906  extending from the cap  902  may be inserted through the holes  806  of the ferrule  102 . The guide pins  906  may help to properly align the ferrule  102  with the waveguide  104 . The inner portion of the cap  902  conforms around the ferrule  102 , waveguide  104 , and/or lid  106  such that the inner portion of the cap  902  remains sealed, thereby protecting the waveguide  104  from contaminants due to polishing and/or washing processes. 
     The waveguide  104  may be heated to a temperature that causes an expansion of the waveguide  104 , allowing it to align with the studs  112 ,  116  (not shown) of the ferrule  102 , and a glue  108  (not shown), such as an ultraviolent glue and/or other bonding material, may be applied to respective grooves  110  (not shown) of the waveguide  104  and studs  112  of the ferrule  102 , as illustrated in  FIG. 1 . As the waveguide  104  cools, the waveguide  104  is prevented from shrinking accordingly and a tension is created within the waveguide  104  that pulls the polymer waveguide  104  flat and brings each waveguide core  114  (not shown) into a precise position within the narrow studs  116 . 
     The cap  902  protects the waveguide  104  from contamination of polishing dusts and/or washing liquids during assembly of the waveguide connector assembly  800 . Accordingly, the present principles do not suffer from the effects of using polyimide cover films and/or adhesive tape placed over the waveguide  104 , such as tearing of the waveguide  104  and/or result in residual glue on the waveguide  104 . 
     Referring now to  FIG. 11 , a method  1100  for constructing a connector is shown. In block  1102 , a waveguide  104  may be inserted into one or more insertion structures  404 ,  704  of a cap  402 . The insertion structures  404  may include flanges, grooves, tapered structures and/or similarly functioning devices configured to position the waveguide  104  for proper alignment with a ferrule  102  and/or lid  106 . In block  1104 , a ferrule  102  and/or a lid  106  may be inserted into an inner portion of the cap. In an embodiment, the ferrule  102  may be positioned over guiding pins  906  such that holes  806  in the ferrule  102  align with the guiding pins  906 . 
     Block  1106  heats the polymer waveguide  104  and the ferrule  102  until the grooves  110  align with studs  112 . As noted above, the polymer waveguide  104  starts with, e.g., a smaller width between grooves  110  than the width between the studs  112  of the ferrule  102 . Due to CTE mismatch between the materials of the polymer waveguide  104  and the ferrule  102 , the polymer waveguide  104  will expand at a different rate per degree of temperature change, such that at some temperature the widths will be equal. Block  1108  applies, e.g., an ultraviolet curing glue  108  to the grooves  110  and/or the studs  112  and block  1110  positions the polymer waveguide  104  on the ferrule  102 , aligning the grooves  110  and the studs  112 . For example, glue may be inserted inside portions of the ferrule  102 , waveguide  104 , and/or lid  106  while the components are inserted into the cap. 
     Block  1112  applies pressure to the polymer waveguide  104  using, e.g., the glass lid  106 . Block  1114  cures the glue by applying, e.g., ultraviolet light. This locks the grooves  110  and the studs  112  together. In an embodiment, the ferrule  102 , waveguide  104 , and/or lid  106  may be polished using one or more polishing techniques and/or cleansed to remove any polishing dusts and/or unwanted contaminants from a portion of the waveguide assembly  100 , as shown in block  1116 . Because the cap seals the exposed portion of the waveguide  104 , polishing dusts and/or unwanted contaminants do not form on the waveguide  104  used for silicon photonic packaging. 
     Block  1118  then removes the pressure from the polymer waveguide  104  and allows the polymer waveguide  104  and the ferrule  102  to cool. As they cool, the polymer waveguide  104  attempts to contract more quickly than the ferrule  102 , creating a tension within the material of the polymer waveguide  104 . This tension pulls the cores  114  precisely into position. In block  1120 , the assembled connector may then be coupling to a silicon optical circuit by adiabatic coupling processes for silicon photonic packaging. 
     Reference in the specification to “one embodiment” or “an embodiment” of the present principles, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present principles. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment. 
     It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as readily apparent by one of ordinary skill in this and related arts, for as many items listed. 
     Having described preferred embodiments of a single-mode polymer waveguide connector assembly device (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments disclosed which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.