Optical fiber connector assembly comprising a multi-fiber ferrule and a thermoplastic adhesive and method of manufacturing the same

Abstract

A fiber optic connector assembly and related method of manufacture utilizes a thermoplastic adhesive material disposed between a stripped region of an optical fiber and a microchannel of a ferrule body, wherein the thermoplastic material is configured to retain a plurality of optical fibers. A method of manufacture includes providing a thermal gradient between a front end face and a back end face of the ferrule body, extending a stripped portion of an optical fiber through a molten thermoplastic adhesive disposed between the optical fiber and a ferrule microchannel, and solidifying the thermoplastic adhesive. The thermal gradient allows the thermoplastic material to reach a sufficiently high temperature while not compromising the dimensional integrity of the front end face. Due to the thermal gradient process, outermost microchannels of a microchannel array can be spaced apart a first distance at the front end face of the ferrule and a second, smaller distance at the back end face. The crystallinity of the ferrule body at the front end face can be different than the crystallinity at the back end face.

Description

[0001] Priority application

[0002] This application claims priority to U.S. Provisional Application No. 63 / 546,631, filed October 31, 2023, the contents of which are incorporated herein by reference in their entirety. Background Technology

[0003] This disclosure generally relates to optical fibers, and more specifically, to optical fiber connector assemblies comprising multiple fiber ferrules, and methods for manufacturing optical fiber connector assemblies.

[0004] Fiber optics are widely used in a variety of applications, including in the telecommunications industry for voice, video, and data transmission. In telecommunications systems using fiber optics, there are typically many locations where fiber-optic cables carrying the fibers need to be connected to equipment or other cables. To facilitate these connections, fiber optic connectors (“connectors”) are usually placed at the ends of the cables. The process of terminating the individual fibers from a cable is called “connectorization.” Connectorization can be done at the factory (resulting in “pre-connectorized” or “pre-terminated” cables) or in the field (e.g., using “field-installable” connectors).

[0005] Many different types of fiber optic connectors exist. Multi-fiber optical connectors are most widely used in environments requiring high-density interconnects and / or high bandwidth, such as data centers. Multi-fiber optical connectors are suitable for use with multi-fiber cables and often employ multi-fiber ferrules. An example of a multi-fiber optical connector is the multi-fiber push-in (MPO) connector, which incorporates a mechanical transmission (MT) ferrule and is standardized according to TIA-604-5 and IEC 61754-7. These connectors enable high-density fiber optics, reducing the hardware, space, and effort required to establish large-scale interconnects. Other examples of multi-fiber optical connectors include the MMC connector, commercially available from US Conec LLC, and the SN-MT connector, commercially available from Senko Advanced Components Inc. The MMC connector uses a ferrule known as a "TMT ferrule," which has the same fiber spacing as the MT ferrule but a smaller form factor (i.e., half the height and half the width compared to the MT ferrule). SN-MT connectors use multi-fiber ferrules (“SN-MT ferrules”), which have smaller pin hole diameters and pin hole spacing compared to traditional MT ferrules, and also a smaller form factor. Both MMC connectors and SN-MT connectors are sometimes referred to as very small form factor (VSFF) connectors.

[0006] Multi-fiber ferrules typically comprise glass-reinforced polymer materials and are manufactured through molding. For MT, TMT, and SN-MT ferrules, fiber alignment depends on the spacing and eccentricity of the fiber micropores and alignment pin holes, where alignment is determined by the alignment pins during mating. Key elements of fiber alignment include the ability to maintain extremely tight dimensional tolerances during ferrule molding and the characteristics of the alignment pins (e.g., shape, tolerances, and material composition).

[0007] Despite the widespread use of MPO connectors and the increasing adoption of VSFF connectors in data center environments, challenges remain in manufacturing these connectors. Termination of multi-fiber ferrules is a time-consuming, multi-step process. One bottleneck in terminating multi-fiber ferrules involves using a two-part thermosetting epoxy resin as an adhesive to bond the inserted optical fibers. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers containing one or more epoxy groups. In a typical epoxy-based termination process, epoxy material is injected or extracted (e.g., by suction) through microchannels in the ferrule where the fiber is inserted or present, and the ferrule with the fiber and uncured epoxy is placed in a curing oven for thermosetting (e.g., at 100°C for 20 minutes, or another suitable time and temperature). The extended time and temperature ranges facilitate batch processing (i.e., curing many ferrules loaded with epoxy and fiber at once), which leads to production bottlenecks due to subsequent processing steps performed on individual ferrules (e.g., polishing). Shortening the epoxy curing time at higher temperatures is generally not feasible because the ferrule should not be exposed to temperatures significantly above 100°C (e.g., no more than 125°C-150°C) to avoid loss of dimensional integrity, which may inhibit proper fiber alignment during connector mating.

[0008] The technical standard known as GR-1435-CORE (also simply "GR-1435") outlines the requirements, characteristics, performance standards, and features of single-mode multi-fiber optical connectors. GR-1435 is designed to test the lifespan performance and reliability of connectors through a series of lifespan performance tests, including environmental and mechanical tests. These tests (typically performed by a third-party testing laboratory on a set of 15 samples provided by the product manufacturer) are designed to simulate the stresses that connectors may encounter throughout their lifecycle, including manufacturing, storage, transportation, operation, handling, and aging. GR-1435 testing includes uncontrolled environment testing, controlled environment testing, and mechanical testing. As part of the rigorous GR-1435 testing regime, fiber optic termination connectors undergo multiple thermal cycles under mechanical loads (e.g., multiple cycles from -10°C to 60°C). Besides epoxy resin, relatively few adhesive materials are available that can bond optical fibers to multi-fiber ferrules and reliably pass GR-1435 certification tests.

[0009] The art continues to seek improved fiber optic connector assemblies and methods of manufacturing thereof to reduce the time required to terminate and bond fibers in multi-fiber ferrules, thereby increasing throughput and reducing manufacturing costs without compromising ferrule dimensional integrity or fiber mechanical retention. Summary of the Invention

[0010] This disclosure provides an optical fiber connector assembly and a related manufacturing method utilizing a thermoplastic adhesive material disposed between a stripped region of an optical fiber and microchannels of a ferrule body, wherein the thermoplastic material is configured to hold multiple optical fibers within the ferrule body. The thermoplastic adhesive material can have a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C. The crystallinity of the ferrule body at a first (e.g., front) end face can differ from that at an opposing second (e.g., rear) end face, for example, this could be due to a thermal gradient applied between the front and rear end faces, where the temperature of the front end face (where the multiple optical fibers terminate) is lower than that of the rear end face. The higher temperature conditions experienced at the rear end face may cause the spacing between the arrayed microchannels at the rear end face to vary more than the spacing between the arrayed microchannels at the front end face, such that the outermost microchannels of the array are spaced apart by a first distance at the front end face and by a smaller second distance at the rear end face. Maintaining the spacing of the microchannels at the front end face (i.e., dimensional integrity) facilitates fiber alignment during connector mating. A method for manufacturing an optical fiber connector assembly includes: providing a thermal gradient between a front end face and a rear end face of a ferrule body, causing a stripped portion of an optical fiber to extend through a molten thermoplastic adhesive disposed between the stripped portion and a plurality of microchannels of the ferrule body, and curing the thermoplastic adhesive material in the microchannels between the stripped portion of the optical fiber and the ferrule body.

[0011] In one exemplary aspect, a fiber optic connector assembly includes a ferrule body comprising a polymer material, the ferrule body having a front end face, a rear end face, and a plurality of microchannels defined within the ferrule body and extending through the front end face. The fiber optic connector assembly also includes a plurality of optical fibers extending through the ferrule body and terminating at the front end face, wherein each of the plurality of optical fibers includes a stripped region, and the stripped region of each optical fiber extends through a corresponding microchannel of the plurality of microchannels. The fiber optic connector assembly also includes a thermoplastic adhesive material disposed in the plurality of microchannels between the stripped regions of the plurality of optical fibers and the ferrule body, and configured to retain the plurality of optical fibers within the ferrule body, wherein the thermoplastic adhesive material has a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C.

[0012] In other exemplary aspects, a fiber optic connector assembly includes a ferrule body comprising a polymer material having a front end face, a rear end face, and a plurality of microchannels defined within the ferrule body and extending through the front end face. The fiber optic connector assembly further includes a plurality of optical fibers extending through the ferrule body and terminating at the front end face, wherein each of the plurality of optical fibers includes a stripped region, and the stripped region of each optical fiber extends through a corresponding microchannel of the plurality of microchannels. The fiber optic connector assembly further includes a thermoplastic adhesive material disposed in the plurality of microchannels between the stripped regions of the plurality of optical fibers and the ferrule body, and configured to retain the plurality of optical fibers within the ferrule body. The ferrule body includes at least one of the following features: (i) the crystallinity of the ferrule body at a first end face differs from the crystallinity at a second end face; and (ii) at least some of the plurality of microchannels are arranged in a one-dimensional array, wherein the outermost microchannels of the one-dimensional array are spaced apart by a first distance at the front end face and by a second distance at the rear end face, wherein the second distance is smaller than the first distance.

[0013] In other exemplary aspects, a method for manufacturing an optical fiber connector assembly is provided, the optical fiber connector assembly comprising a ferrule body and a plurality of optical fibers, the ferrule body comprising a polymer material, and each of the plurality of optical fibers comprising a stripped region. One method step includes heating at least a portion of the ferrule body and providing a thermal gradient between a front end face and a rear end face of the ferrule body, wherein the front end face is at a lower temperature than the rear end face. Another method step includes inserting stripped portions of the plurality of optical fibers through the rear end face of the ferrule body into a plurality of microchannels defined in the ferrule body and extending through the front end face of the ferrule body, such that the stripped portions of the plurality of optical fibers extend at least to the front end face. Another method step includes extending the stripped portions of the plurality of optical fibers through a molten thermoplastic adhesive disposed between the stripped portions of the optical fibers and the plurality of microchannels. Another method step includes curing the thermoplastic adhesive in the plurality of microchannels between the stripped regions of the optical fibers and the ferrule body.

[0014] In addition, the exemplary optical cable assembly includes an optical fiber connector assembly as disclosed herein, mounted on the optical cable.

[0015] Additional features and advantages will be set forth in the following detailed description, and some of these additional features and advantages will be apparent to those skilled in the art of optical connection technology. It should be understood that the foregoing general description, the following detailed description, and the accompanying drawings are merely exemplary and intended to provide an overview or framework for understanding the nature and characteristics of the claims. Attached Figure Description

[0016] The accompanying drawings are included to provide further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operation of various embodiments. Features and attributes associated with any illustrated or described embodiment may be applied to other embodiments shown, described, or understood based on this disclosure.

[0017] Figure 1 This is a perspective view of an optical fiber connector assembly and an associated optical fiber cable forming an optical cable assembly according to one embodiment, wherein the optical fiber connector assembly includes an MT-type multi-fiber ferrule having microchannels adapted to receive thermoplastic adhesive material for securing optical fibers therein.

[0018] Figure 2 yes Figure 1 An exploded perspective view of the optical fiber cable assembly.

[0019] Figure 3 yes Figure 1 and 2 The front elevation view of the MT-type multi-fiber ferrule shows a one-dimensional array of microchannels extending to the front end face of the ferrule.

[0020] Figure 4A This is a front perspective view of a first TMT-type multi-fiber ferrule according to one embodiment, the first TMT-type multi-fiber ferrule comprising a one-dimensional array of microchannels adapted to receive thermoplastic adhesive material for securing optical fibers therein.

[0021] Figure 4B yes Figure 4A A perspective cross-sectional view of a TMT-type multi-fiber ferrule.

[0022] Figure 5 It includes according to Figure 4A and 4B A perspective view of a TMT-type multi-fiber ferrule fiber optic connector assembly.

[0023] Figure 6A This is a perspective view of a second TMT-type multi-fiber ferrule according to one embodiment, the second TMT-type multi-fiber ferrule comprising a two-dimensional array of microchannels adapted to receive thermoplastic adhesive material for securing optical fibers therein.

[0024] Figure 6B yes Figure 6A Front elevation view of the TMT type multi-fiber ferrule.

[0025] Figure 7 It is a perspective view of a one-dimensional array of optical fibers, including its stripped and unstripped portions.

[0026] Figure 8It is a rear-view, partially transparent view of a TMT-type multi-fiber ferrule having first and second arrays of optical fibers terminated therein, wherein the first and second stripes extend from the rear central groove of the ferrule.

[0027] Figure 9 This is a front elevation view of a part of a multi-fiber ferrule, showing the optical fibers held within the microchannels of the ferrule using a thermoplastic adhesive material.

[0028] Figure 10 This is a comparison chart of the fiber ribbon pull-out strength of optical fibers held in the ferrule using three different methods: (i) adding thermoplastic adhesive material and then inserting the fiber; (ii) inserting the fiber and then adding thermoplastic adhesive material; and (iii) conventional epoxy bonding.

[0029] Figure 11 This is a front perspective view of a TMT-type multi-fiber ferrule, which is subjected to a thermal gradient between its rear and front faces, as applicable during the execution of a method for manufacturing a fiber optic connector assembly according to embodiments disclosed herein.

[0030] Figure 12 This is a perspective view of the first retainer, which is configured to receive a multi-fiber ferrule and allows a thermal gradient to be applied between the rear and front faces of the multi-fiber ferrule as part of a method of manufacturing a fiber optic connector assembly.

[0031] Figure 13A yes Figure 12 An enlarged perspective view of the front of the retainer, in which the multi-fiber ferrule is received in its front aperture.

[0032] Figure 13B yes Figure 13A Side elevation view of the retainer and multi-fiber ferrule.

[0033] Figure 13C yes Figures 13A-13B Side cross-sectional view of the retainer and multi-fiber ferrule.

[0034] Figure 14A yes Figure 12 A side elevation view of a portion of the induction coil and holder, with the induction coil in the retracted position.

[0035] Figure 14B yes Figure 14A A side elevation view of the induction coil and holder portion, wherein the induction coil is in an extended position, the extended position being arranged to induce heating of the holder.

[0036] Figure 14C It shows an arrangement close to the fiber optic transport equipment. Figures 14A-14BThe induction coil and retainer section of the optical fiber transport device are used to insert the optical fiber into the ferrule received by the retainer.

[0037] Figure 14D This shows the process after the fiber-loaded ferrule retracts from the retainer. Figure 14C The induction coil, the holding device, and the fiber optic transport equipment.

[0038] Figure 15A and 15B Bottom and top perspective views are provided for multiple optical fibers held in a multi-fiber ferrule with thermoplastic adhesive material before the fiber ends are trimmed and polished.

[0039] Figure 16 This is a perspective view of a second retainer configured to receive a multi-fiber ferrule, combined with an induction heating coil and a gas conduit to allow a thermal gradient to be applied between the rear and front faces of the ferrule as part of a method of manufacturing a fiber optic connector assembly.

[0040] Figure 17 It is a top plan view of an optical fiber array including stripped and unstripped portions, wherein thermoplastic adhesive material is pre-applied to the areas of the stripped portions in preparation for insertion into multi-fiber ferrules.

[0041] Figure 18 It is a differential scanning chromatogram of the relationship between heat flux and temperature for the first and second heating cycles of two multi-fiber ferrules (i.e., TMT ferrule and MT ferrule). Detailed Implementation

[0042] Various embodiments will be further illustrated by examples in the following description. Generally, this specification relates to an optical fiber connector assembly and a related manufacturing method utilizing a thermoplastic adhesive material disposed between a stripped region of an optical fiber and microchannels of a ferrule body, wherein the thermoplastic material is configured to retain multiple optical fibers within the ferrule body. In some embodiments, the thermoplastic adhesive material has a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C. In some embodiments, the crystallinity of the ferrule body at a first (e.g., front) end face differs from its crystallinity at an opposing second (e.g., rear) end face. In some embodiments, the microchannels defined in the ferrule body are arranged in an array, wherein the outermost microchannels of the array are spaced apart by a first distance at the front end face and by a smaller second distance at the rear end face.

[0043] Before discussing novel fiber optic connector assemblies and manufacturing methods, two types of fiber optic connectors configured to hold multiple fibers will be introduced for ease of discussion. However, those skilled in the art of optical connections will understand that the specific connector types disclosed herein are merely examples, and the general principles disclosed regarding the multi-fiber ferrules and other components shown in the following figures can be applied to other connector designs.

[0044] Figure 1 The image shows a first example of a fiber optic connector 10 (also referred to as "optical connector 10", or simply "connector 10"), in which... Figure 2 An exploded view of the connector is provided, and Figure 3 An enlarged front view of the connector's ferrule 16 is provided. Connector 10 is shown as an MTP® connector, a specific type of MPO connector (MTP® is a trademark of US Conec LLC). Figure 1 As shown, connector 10 can be mounted on optical cable 12 (“cable”) to form optical cable assembly 14. Connector 10 includes a ferrule 16, a housing 18 received on the ferrule 16, a slider 20 received on the housing 18, and a sheath 22 received on the cable 12. The ferrule 16 includes a body 17 and is spring-biased within the housing 18 such that the front portion 24 of the ferrule 16 extends beyond the front end 26 of the housing 18. An optical fiber (not shown) carried by the cable 12 extends through a microchannel (also called a micro-hole / micro-bore or simply a hole) 28 defined in the ferrule 16 and then terminates at or near the front end face 30 of the ferrule 16. The optical fiber is secured to the microchannel of the ferrule 16 using an adhesive material (e.g., epoxy resin according to the prior art, or thermoplastic adhesive as disclosed herein). Figure 3 Within 28), and when housing 18 is inserted into an adapter, socket, etc., it can be used for fiber optic coupling with mating components (e.g., another fiber optic connector; not shown).

[0045] like Figure 2 As shown, connector 10 also includes a ferrule sleeve 32, a guide pin assembly 34, a spring 36, a crimp body 38, and a crimp ring 40. The integral ferrule sleeve 32 is received in the rear portion 42 of the ferrule 16 to help support the extension to the microchannel 28 (e.g., Figure 1 The optical fiber (as shown) extends through an aperture (not shown) defining a passage through the ferrule sheath 32. The guide pin assembly 34 includes a pair of guide pins 44 extending from the pin retainer 46. Features on the pin retainer 46 engage with features on the guide pins 44 to retain portions of the guide pins 44 within the pin retainer 46. When the connector 10 is assembled, the pin retainer 46 is positioned against the rear surface of the ferrule 16, and the guide pins 44 extend through pin holes 48 (as shown) provided in the ferrule 16. Figure 1 (as shown), so as to highlight the front end face 30 beyond the ferrule 16.

[0046] Both the ferrule 16 and the guide pin assembly 34 are biased by a spring 36 to a forward position relative to the housing 18. More specifically, the spring 36 is positioned between the pin retainer 46 and a portion of the crimping body 38. The crimping body 38 is inserted into the housing 18 when the connector 10 is assembled and includes a latching arm 50 that engages with a recess 52 in the housing 18. The spring 36 is compressed at this point and applies a biasing force to the ferrule 16 via the pin retainer 46. The rear portion 42 of the ferrule 16 defines a flange that interacts with a shoulder or stop formed within the housing 18 to retain the rear portion 42 of the ferrule 16 within the housing 18. The rear portion 42 of the ferrule 16 also includes a recess (not shown) configured to receive at least the front portion of the ferrule sheath 32.

[0047] In a manner not shown in the figure, an aramid yarn or other strength component from cable 12 is positioned on end 54 of a crimping body 38 projecting rearward from housing 18. The aramid yarn is secured to end 54 by a crimping ring 40, which slides over end 54 and deforms after positioning the aramid yarn. Figure 1 As shown, the sheath 22 covers this area and provides stress relief for the optical fibers emanating from the optical cable 12 by limiting the degree to which the connector 10 can bend relative to the optical cable 12.

[0048] Figure 3 This is a front elevation view of the insert 16, showing a one-dimensional array of microchannels 28 extending to the front end face 41 of the insert. As shown, the front end face 41 is reduced in height and width compared to the rear portion 42 of the insert. The insert 16 may comprise a polymeric material, optionally reinforced with inorganic fillers such as glass fibers or glass beads. In some embodiments, the insert body comprises at least 50% by weight (or at least 60%, 70%, or 80% by weight) of glass-filled material, and the polymer of the insert body comprises a polymer such as polyphenylene sulfide. Although in Figure 3 Only a single linear array of microchannels 28 is shown in the image, but it should be understood that in some embodiments, the multi-fiber connector may contain multiple rows of microchannels.

[0049] Figure 4A and 4B Another exemplary multi-fiber (i.e., first TMT type) ferrule 66 comprising a one-dimensional array of microchannels 78 is shown, wherein Figure 4A This is a front perspective view of the ferrule 66 and Figure 4BThis is a perspective cross-sectional view. The ferrule 66 includes a ferrule body 67 having a front face 70, a rear face 71, a lateral surface 73, a top surface 75, and a bottom surface 76. An upper recess 81 is defined in the top surface 75 and extends to the front face 70. The edge of the upper recess 81 is defined by a first forward surface 82, two first inclined surfaces 83, and two first lateral surfaces 84. A lower recess 85, wider than the upper recess 81, is defined in the bottom surface 76 and also extends to the front face 70, wherein the edge of the lower recess 85 is defined by a second forward surface 86, two second inclined surfaces (not shown), and two second lateral surfaces 88. A pin hole 68 adapted to receive an alignment pin (not shown) extends parallel to the lateral surface 73 from the front face 70 to the rear face 71. A rear center recess 69 extends from the rear face 71 into the ferrule body 67 and may have sufficient width and height to receive unstripped portions of multiple optical fibers (not shown). Microchannel 78 extends along plane E from an intermediate surface 77 defining a portion of the rear central recess 120 to a front end face 70, wherein the intermediate surface 77 is disposed between the front end face 70 and the rear end face 71. Microchannel 78 includes an extension 78' adjacent to the intermediate surface 77 and includes a chamfered transition 79 (disposed between the intermediate surface 77 and the front end face 70) to facilitate the insertion of a stripped portion of an optical fiber (not shown) through the rear central recess 69 toward the front end face 70. In the various embodiments disclosed herein, a thermoplastic adhesive material (not shown) may be disposed between the microchannel 78 and the optical fiber contained within the microchannel (e.g., as shown in the image). Figure 7-8 (as shown) between, wherein thermoplastic adhesive material may also be disposed within the rear center groove 120.

[0050] Figure 5 This is a perspective view of a fiber optic connector assembly 90, which includes a TMT-type multi-fiber ferrule 66 (according to...). Figure 4A and 4B The TMT-type multi-fiber ferrule has a microchannel 78 extending to the front end face 70 and a pin hole 78, wherein the ferrule 66 is received by a housing 91 having an associated sheath 92, and wherein the optical cable 94 extends rearward from the sheath 92.

[0051] Figures 6A-6B Another TMT-type multi-fiber ferrule 116 is shown, featuring a first linear array 127-1 and a second linear array 127-2 with microchannels 128. Figure 6A This is a perspective view of ferrule 116 and Figure 6BThis is its front elevation view. The insert 116 includes an insert body 117 having a front end face 120, a rear end face 121, a lateral surface 123, a top surface 125, and a bottom surface 126. An upper recess 131 is defined in the top surface 125 and extends to the front end face 120. The edge of the upper recess 131 is defined by a first forward surface 132, two first inclined surfaces 133, and two first lateral surfaces 134. A lower recess 135, wider than the upper recess 131, is defined in the bottom surface 126, partially defined by a second forward surface 136, and also extends to the front end face 120. A first linear array 127-1 of microchannels 128 is arranged along a first plane P1, and a second linear array 127-2 of microchannels 128 is arranged along a second plane P1 parallel to the first plane P1, wherein all microchannels 128 extend from the front end face to the rear central recess defined in the rear end face 121 (e.g., Figure 8 The 119 shown is similar to... Figure 4B The rear central groove 69 shown herein. In the various embodiments disclosed herein, the thermoplastic adhesive material ( Figure 8 and 9 139 shown in the diagram can be positioned in the microchannel 128 with an optical fiber (e.g., contained in the microchannel) Figure 7-8 Between 140A-140L shown, a thermoplastic adhesive material may also be disposed within the rear center recess. A pin hole 118 adapted to receive an alignment pin (not shown) extends parallel to the lateral surface 123 from the front end face 120 to the rear end face 121.

[0052] Figure 7 This is a perspective view of a one-dimensional array of twelve optical fibers 140, including unstripped portions 140A-140L and stripped portions 142A-142L of the fibers, wherein the stripped portions 142A-142L of the fibers 140 have fiber ends 141A-141L. Although twelve optical fibers 140 are shown, it should be understood that any suitable number of optical fibers can be provided in a one-dimensional or two-dimensional array.

[0053] Various ferrules for multi-fiber optical connectors have been introduced; now the use of thermoplastic adhesive materials for securing (bonding) optical fibers to multi-fiber ferrules will be described.

[0054] Figure 8 This is a rear-view, partially transparent view of a TMT-type multi-fiber ferrule 116A, the ferrule having first and second arrays of optical fibers terminated therein, wherein such arrays of optical fibers radiate from a first strip 146-1 and a second strip 146-2, the first and second strips extending from a rear central groove 119 defined in a rear end face 121 of the ferrule 116A. The ferrule 116A is substantially similar to Figures 6A-6BThe insert 116 shown includes an insert body 117A having a front end face 120, a rear end face 121, a lateral surface 123, a top surface 125 (defining an upper recess 131), and a bottom surface 126. A pin hole 118 adapted to receive an alignment pin (not shown) extends from the front end face 120 to the rear end face 121. A first linear array 127-1 and a second linear array 127-2 of microchannels 128 (each having a chamfered transition 129) extend between the front end face 120 and the rear central recess 119. A first strip 146-1 includes unpeeled portions 140A-1 to 140L-1, such that peeled portions (e.g., 142A-1 as shown) extend through the microchannels 128 in the first array 127-1 of microchannels 128. Similarly, the second strip 146-2 includes unstripped portions 140A-2 to 140L-2, such that stripped portions (e.g., 142L-2 as shown) extend through the microchannels 128 in the second array 127-2 of microchannels 128. A thermoplastic adhesive material 139 is disposed in each microchannel 128 to bond optical fibers (e.g., stripped portions of the optical fibers emanating from strips 146-1, 146-2) to the ferrule body 117A. Preferably, the same thermoplastic adhesive material 139 is disposed in the rear central recess 119 to further bond the optical fiber strips 146-1, 146-2 and / or the unstripped portions 140A-1 to 140L, 140A-2 to 140L-2 to the ferrule body 117A.

[0055] When a thermoplastic adhesive material is disposed between the microchannel of the ferrule and the stripped optical fiber arranged in the microchannel, the thermoplastic adhesive material can have a substantially annular shape, for example... Figure 9 As shown. Figure 9 This is a front elevation view of a portion of a multi-fiber ferrule 116, showing stripped portions 142A to 142D of optical fibers held within microchannels 128 (defined in the front end face 121 of the ferrule 116) using a thermoplastic adhesive material 139, with termination ends 141A to 141D visible along the front end face 121. As shown, the thermoplastic adhesive material 139 may have an annular shape to fill the space between the outer surface of the stripped portions 142A to 142D of the optical fibers and the microchannels 128.

[0056] The aforementioned thermoplastic adhesive materials replace traditional epoxy adhesives used to secure optical fibers to ferrules. One challenge associated with using thermoplastic adhesive materials is the relative scarcity of adhesives, besides epoxy, capable of bonding optical fibers to multi-fiber ferrules and reliably passing the GR-1435 certification test. It has been determined that an ideal thermoplastic adhesive material should, in combination, possess a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C. The applicant has discovered that certain thermoplastic adhesive materials may comprise an adhesive polymer that is at least one of polyamide, polyurethane, polyolefin, ethylene-vinyl acetate, styrene block copolymer, polyester, copolyamide, copolyester, or mixtures thereof. Such thermoplastic adhesive materials may also contain one or more additives, including (but not limited to) antioxidants, color concentrates, viscosity modifiers, tackifiers, and fillers. Selected commercially available thermoplastic adhesive materials considered by the applicant are listed in Table 1 below, wherein these adhesives are considered to contain polyamide / copolyamide or polyester / copolyester as a major component.

[0057]

[0058] Table 1: Examples of Selected Thermoplastic Hot Melt Adhesives

[0059] To demonstrate the connector performance of thermoplastic adhesive materials (also known as "thermo-melt" materials), 12 fiber optic MPO connectors (including MT ferrules) were manufactured using Kraton Uni-Rez™ 2626 as the fiber optic adhesive and compared with the same type of MPO connectors using conventional Epo-Tek® 353 ND epoxy resin as the fiber optic adhesive. For one set of MPO connectors manufactured using Kraton Uni-Rez™ 2626 (i.e., "thermo-melt preferred"), the thermoplastic adhesive material was preloaded onto the back of the ferrule and melted using a thermoelectric heater before fiber insertion. For another set of MPO connectors manufactured using Kraton Uni-Rez™ 2626 (i.e., "fiber preferred"), the thermoplastic adhesive material was preloaded onto the stripped portion of the fiber, the ferrule was heated, and the thermoplastic-coated fiber was inserted into the ferrule. For MPO connectors manufactured using Epo-Tek® 353 ND epoxy resin, a typical epoxy termination procedure was employed, pre-filling the ferrule with uncured epoxy resin and curing at 100°C for 20 minutes after fiber insertion. All MPO connectors were polished and measured in the same manner for direct comparison. Fiber retention force was tested using a fiber optic tensile tester. The applicant considers an average retention force of 2 lbf per fiber (i.e., a total force of 24 lbf for 12 fibers) to be a reasonable minimum pull-out strength value for commercial use. Figure 10As shown, the total retention force of the 12 optical fibers in an MPO connector bonded with hot melt material is between approximately 25 and 35 lbf. In a comparable range to that of an MPO connector bonded with epoxy resin, the total retention force of the 12 optical fibers in an MPO connector bonded with epoxy resin is between approximately 25 and 50 lbf.

[0060] Another challenge associated with securing optical fibers to polymer-based multi-fiber ferrules using thermoplastic adhesives is maintaining compliance with IEC 61755-3-31 specifications regarding optical interface end-face geometry under environmental conditions that the ferrule may be exposed to during normal use. Specifically, IEC-61755-3-31 requires the fiber protrusion height relative to the ferrule end face to be between 1 µm and 3.5 µm, and to have a certain amount of coplanarity. The latter is expressed as “negative coplanarity” and is actually the distance between the lowest fiber protrusion in the array and the best-fit plane that passes through all fiber protrusions in the array. Environmental conditions that the ferrule may be exposed to include prolonged exposure to high temperatures and humidity (thermal and humidity aging), as well as temperatures cycling between relatively hot and cold conditions (thermal cycling). For example, GR-1435 includes tests for these and other environmental conditions that cable assemblies with multi-fiber connectors may experience. The applicant found that maintaining coplanarity according to IEC-61755-3-31 may be particularly challenging, possibly due to the increased softness of thermoplastic materials at high temperatures during thermal aging and / or thermal cycling tests.

[0061] One potential approach to address this challenge is to blend silane coupling agents with thermoplastic materials used as adhesives. Silane coupling agents can increase adhesion to optical fibers and increase the stiffness of thermoplastic adhesive materials. A variety of coupling agents can be used, including, but not limited to, organofunctional silanes having one or more epoxy, amino, mercapto, acrylate, and / or other organic functional groups for reaction with organic materials. In some embodiments, the silane coupling agent may also include one or more alkoxy, hydroxyl, and / or other functional groups for reaction with inorganic materials. In some embodiments, about 0.1 to about 10 parts by weight of silane coupling agent may be present per 100 parts by weight of thermoplastic polymer material. In various embodiments, about 0.1, about 0.5, about 1, about 2, about 4, about 6, about 8, or about 10 parts by weight of silane coupling agent, or any combination thereof, may be present per 100 parts by weight of thermoplastic polymer material.

[0062] Another challenge associated with using thermoplastic adhesives instead of traditional epoxy adhesives to secure optical fibers to ferrules is that many thermoplastic adhesives require high temperatures to reach the flowable conditions that would allow them to occupy the microchannels in the ferrule and permit fiber insertion—temperature values ​​traditionally considered too high for polymer-based multi-fiber ferrules. Typical polymer-based ferrule materials include (thermoplastic) polyphenylene sulfide (PPS) and inorganic fillers such as glass fibers or glass beads. Such polymer-based ferrules should generally not be exposed to temperatures significantly above 100°C (e.g., no more than 125°C–150°C in absolute limits) to avoid plastic deformation through cold crystallization, leading to dimensional changes that can inhibit proper fiber alignment during connector mating and thus degrade optical performance. This is particularly problematic if the cold crystallization temperature of the polymer material in the polymer-based ferrule is below the melting point of the thermoplastic adhesive.

[0063] The applicant has observed that when glass-reinforced polyphenylene sulfide (PPS) TMT ferrules are heated at 180°C for one minute, the distance between the guide pin holes shrinks by approximately 3 to 8 µm, which is attributed to cold crystallization. This shrinkage also leads to a reduction in the distance between the microchannels, with the effect being most pronounced when considering the distance between the outermost microchannels closest to the guide pin holes. Figure 18 As shown, cold crystallization occurred in the differential scanning spectroscopy (DSC) scan of glass-filled polyphenylene sulfide inserts (MT and TMT types) at temperatures close to 150℃-160℃.

[0064] Kraton Uni-Rez™ 2626 thermoplastic adhesive requires ferrule temperatures exceeding 160°C to melt the adhesive and insert the fiber into the ferrule. Such temperatures pose a risk of ferrule deformation. While low-temperature thermoplastic adhesives are commercially available, other desirable properties (e.g., modulus of elasticity) are compromised, rendering such adhesives unsuitable for use in commercial fiber optic connectors.

[0065] To allow for the bonding of optical fibers to polymer-based multi-fiber ferrules using high-temperature thermoplastic adhesives, the various methods disclosed herein involve applying a thermal gradient between the front and rear faces of the ferrule, where the temperature of the front face (where multiple fibers terminate) is lower than that of the rear face. This approach aims to allow sufficiently high temperatures to soften or melt the thermoplastic adhesive material at the rear of the ferrule, while keeping the front face (where dimensions are more critical) well below its cold crystallization temperature, thus avoiding negative impacts on connector performance from dimensional variations of the front face. Another advantage of providing a cooler front face is that it helps control the amount of thermoplastic adhesive flowing out of the microchannels along the front face, thereby reducing the steps required for adhesive removal and subsequent fiber end polishing.

[0066] exist Figure 11 The figure schematically illustrates the application of a thermal gradient between opposing faces of a multi-fiber ferrule. The figure shows a TMT-type multi-fiber ferrule 66A having a front face 70 and a rear face 71 defined by a side surface 73, wherein microchannels 78A-78P extend to the front face 70 and are arranged in a one-dimensional array. The outermost microchannels 78A, 78P are arranged closest to two guide pin holes 68 extending parallel to the side surface 73. As shown, the rear portion of the ferrule 66A (including the rear face 71) is subjected to high-temperature conditions (e.g., 150°C to 220°C), while the front face 70 is subjected to lower-temperature conditions (e.g., below 150°C), which can be provided when optical fibers and thermoplastic adhesive material (not shown) are supplied to the ferrule 66A (e.g., by insertion in a direction from the rear face 71 toward the front face 70). Keeping the front face 70 at a lower temperature reduces the risk of cold crystallization and dimensional changes at the front face 70, but the high temperature conditions experienced at the rear of the ferrule 66A may be sufficient to soften and / or melt the thermoplastic adhesive material and allow the optical fiber to be inserted through the microchannels 78A-78P.

[0067] As disclosed herein, applying a thermal gradient from front to back of a polymer-based multi-fiber ferrule can modify the ferrule in several ways. First, if cold crystallization occurs at the back of the ferrule instead of the front, the crystallinity of the ferrule body at the first end face can differ from that at the second end face. Additionally, the ferrule dimensions (including the spacing between the outermost microchannels of the one-dimensional array) can be varied at the back end face. In this case, if the ferrule contains multiple microchannels arranged in a one-dimensional array, the outermost microchannels of the one-dimensional array can be spaced apart by a first distance at the front end face and by a second distance at the back end face, where the second distance is smaller than the first distance. Using a thermal gradient to maintain a lower temperature at the front end face preserves the dimensional integrity of this critical connector surface while allowing sufficiently high temperatures to allow the thermoplastic adhesive material to bond the optical fiber to the polymer-based multi-fiber ferrule.

[0068] Various methods can be used to establish a thermal gradient on a multi-fiber ferrule. In some embodiments, the ferrule may be received by a clamp such that the rear portion of the ferrule is in conductive contact with the clamp, while the front portion (including the front end face) of the ferrule is not in contact with the surface of the clamp. For example, the front portion of the ferrule may protrude into air (or another cooling medium, optionally supplied in a forced manner as a gas (or liquid) jet or flow), while the rear portion of the ferrule is arranged to be in conductive contact with the clamp. Various types of heating can also be used, such as thermoelectric heating, induction heating, laser heating, and / or resistance heating; however, induction heating has been found to be particularly advantageous due to its rapid and highly controllable characteristics. In some embodiments, the ferrule may be received in a retainer close to the induction coil (where the front portion of the ferrule is not in conductive contact with any part thereof), wherein relative movement between the retainer and the induction coil can be achieved to heat the retainer, thereby heating the rear portion of the ferrule received by the retainer. Exemplary retainer material may be steel or another magnetically responsive material suitable for induction heating.

[0069] Figure 12 This is a perspective view of a first retainer 150 configured to receive a multi-fiber ferrule (not shown) and to apply a thermal gradient between the rear and front faces of the ferrule. The retainer 150 includes a base 151 and a tubular portion 152 terminating at an end 155 defined for receiving the ferrule (e.g., Figure 13A The insert 116 has an opening 156. The tubular portion 152 may be hollow and includes a sensor insert 160 having a slot 162 and being engaged to the tubular portion 152 by a fastener (e.g., a screw) 164. A lateral opening 158 is defined in the tubular portion 152 near the end 155. Further details regarding the tubular portion 152 of the retainer 150 are provided in Figures 13A-13C As shown, these figures provide perspective, side elevation, and cross-sectional views of the tubular portion 152, wherein the rear portion of the insert 116 is received in its orifice 156. Figure 13A As shown, the insert 116 includes a rear end face 121, a rear central recess 119 defined in the rear end face, and a guide pin hole 118 extending to the rear end face 121, wherein the rear end face 121 may be substantially flush with the end 155 of the tubular portion 152. Figure 13B and 13C As shown, the front portion of the insert 116, including the insert front end face 120, does not make conductive contact with the retainer 150 and extends into the hollow interior 157 of the tubular portion 151 near the lateral opening 158. Figure 13CA temperature sensor 166 is also shown, arranged to contact the top surface of the insert 116 to monitor the temperature of the insert 116 during the heating process. In some embodiments, a cooling medium such as air or another fluid may be supplied through the hollow interior 157 and the lateral opening 158 to cool the front portion of the insert 116 (wherein such heating causes conductive heating of the rear portion of the insert 116) while the tubular portion 152 is inductively heated.

[0070] Figures 14A-14B This shows two positions relative to the induction heating coil 170. Figure 12 and Figures 13A-13C The image shows a side elevation view of the tubular portion 152 of the retainer 150, wherein the insert 116 is received by the end 155 of the retainer 150. The induction heating coil 170 includes a central opening 172, the size of which is adapted for external assembly around a portion of the tubular portion 152. Figure 14A The diagram shows that the induction coil 170 is in a retracted position relative to the tubular portion 152, thus preventing induction heating of the tubular portion 152. Figure 14B An induction coil 170 in its deployed position is shown, with the end 155 of the tubular portion 152 arranged in the central opening 172, such that activation of the induction coil 170 can heat the tubular portion 152, thereby causing conductive heating of the rear portion of the insert 116. This can be responsive to... Figure 13C The temperature sensor 166 shown receives signals to control the operation of the induction coil 170 and the optional supply of cooling medium (through the hollow interior 157).

[0071] Figure 14C The arrangement close to the fiber optic transport device 180 is shown. Figures 14A-14BThe fiber optic transport device comprises an induction coil 170 and a retainer tubular portion 152 for inserting an optical fiber 140 into a ferrule 116 received by an end 155 of the tubular portion 152. The induction coil 170 is shown in a retracted position, which can occur before or after heating the tubular portion 152 containing the ferrule 116. In operation, the ferrule 116 is loaded into the end 155 of the tubular portion 152, and the ferrule 116 is provided with the optical fiber 140 and a thermoplastic adhesive material. In some embodiments, the thermoplastic adhesive material is loaded into the ferrule, the ferrule 116 is heated (indirectly, by positioning and activating the induction coil 170), and the optical fiber 140 is inserted into and through the ferrule 116. For example, the thermoplastic adhesive material may initially be provided in the form of a monofilament, and short lengths of monofilament may be cut and placed into a rear central recess 119 of the ferrule 116, thereby extending laterally (i.e., across the width of the rear central recess 119). Alternatively, the thermoplastic adhesive can be dispensed into the rear center recess 119 using a hot melt glue gun or a hot melt spray device. These and other techniques for loading the thermoplastic adhesive into the insert can be performed before the insert 116 is loaded into the retainer 150, so that the insert 116 is pre-loaded with thermoplastic adhesive, or performed afterward.

[0072] In some embodiments, a thermoplastic adhesive material is loaded onto the optical fiber (optionally in combination with the thermoplastic adhesive material supplied to the ferrule 116) before the optical fiber 140 is inserted into the ferrule 116. For example, the thermoplastic adhesive can be applied to the optical fiber 140 by a hot melt glue gun, a hot melt spraying device, an overmolding technique, or as a lamination film. Applying the thermoplastic adhesive to the optical fiber 140 can occur before the fiber termination process or as a step during the termination process.

[0073] Regardless of the technique used to load, apply, or otherwise provide the thermoplastic adhesive to the rear central recess 119 and / or the optical fiber 140, the optical fiber 140 is ultimately partially inserted into and / or penetrated through the ferrule 116, which is heated (indirectly by positioning and activating the induction coil 170), and the remaining length of the optical fiber 140 is inserted into and penetrated through the ferrule 116 to allow the molten thermoplastic adhesive material to be dragged through the microchannels of the ferrule 116. After the thermoplastic adhesive material cools, the ferrule 116, in which the optical fiber 140 is held, can be removed from the end 155 of the tubular portion 152 by achieving relative movement between the tubular portion 152 and the optical fiber handling device 180, where the optical fiber 140 is held by the clamping portion 182 of the optical fiber handling device 180, as... Figure 14D As shown. Therefore, Figure 14D This shows the ferrule 116 containing the optical fiber from the retainer ( Figure 12 and 13AThe tubular portion 152 of -13C (150) after retraction Figure 14C Items.

[0074] Figure 15A and 15B Bottom and top perspective views are provided, respectively, of multiple optical fibers 140A-140L held in a multi-fiber ferrule 116A with thermoplastic adhesive material 139 after bonding with thermoplastic adhesive material but before trimming excess adhesive-coated fiber portions 149 and polishing fiber ends along the front end face 120. Ferrule 116A and... Figure 8 The type shown is the same, having grooves 131, 135 respectively defined in the portions extending between the front end face 120 and the rear end face 121 on the upper surface 125 and the lower surface 126, and having a guide pin hole 118 visible at the rear end face 121.

[0075] Figure 16 This is a perspective view of a second retainer 192 having a retainer end 193 configured to receive a multi-fiber ferrule 116, which is coupled to an induction heating coil 170A and a cooling conduit 200 to allow a thermal gradient to be applied between the rear and front faces of the ferrule 116. The retainer 192 and an associated temperature sensor cable 167 extend through a central opening 172A of the induction heating coil 170A. The retainer end 193 includes an opening 194 configured to receive the ferrule 116 with its rear face facing upward, thereby exposing a rear central recess 119 defined therein. Although not shown, it should be understood that the front portion containing the front face of the ferrule 116 protrudes downward beyond the retainer end 193 to allow the front face to be cooled by a cooling medium (e.g., air or another fluid) supplied through the cooling conduit 200. This cooling can be performed simultaneously with the retainer end 193 being inductively heated by the induction heating coil 170A (when positioned around the retainer end 193) to conduct heat to the rear of the ferrule 116 of the contact retainer 192.

[0076] Various methods can be used as part of the methods described herein for manufacturing fiber optic connector assemblies to apply thermoplastic adhesive material to the ferrule and / or optical fiber.

[0077] If induction heating is used, the ferrule can be started in a cold state. In some embodiments, a thermoplastic adhesive material can be pre-applied to (e.g., coated on) the stripped portion of the optical fiber to better fit the internal dimensions of the ferrule microchannel, thereby facilitating pre-alignment of the optical fiber with the microchannel before the thermoplastic adhesive melts. This pre-application of the thermoplastic adhesive material can include, for example, overmolding, film lamination, spraying, or printing.

[0078] In some embodiments, the thermoplastic adhesive material can be provided as a monofilament material, wherein fragments of the monofilament thermoplastic material can be cut and inserted into the microchannels and / or rear central groove of the insert before heating.

[0079] In some embodiments, thermoplastic adhesive material can be supplied to the desired area of ​​the ferrule and / or the optical fiber using a heating gun or injector.

[0080] In some embodiments, the thermoplastic adhesive material may be provided as a custom-molded plug (optionally including a channel or portion of a channel for the optical fiber) configured to be inserted into the rear central recess of the ferrule.

[0081] Figure 17 It is a top plan view of an optical fiber array 140' including stripped portions 142A-142L and unstripped portions 140A-140L (which may be arranged in a strip 146), wherein thermoplastic adhesive material 139A is pre-applied to the areas of the stripped portions 142A-142L in preparation for inserting the ends 141A-141L of the stripped portions 142A-142L into multi-fiber ferrules (not shown). If the thermoplastic adhesive material 139A is initially in a solid state, the stripped portion 142A-142L between the thermoplastic adhesive material 139A and the fiber ends 141A-141L can be partially inserted into the ferrule (through its micropores). The ferrule is then heated to melt the thermoplastic adhesive material 139A, and the remaining stripped portion 142A-142L is then further inserted into the ferrule so that the molten thermoplastic adhesive material 139A is “dragged” by the stripped portion 142A-142L into the microchannel of the ferrule.

[0082] Figure 18 This is a differential scanning chromatogram showing the relationship between heat flux and temperature for the first and second heating cycles of two multi-fiber ferrules (i.e., the TMT ferrule and the MT ferrule, which includes glass-filled polyphenylene sulfide). The figure illustrates the occurrence of cold crystallization at temperatures close to 150°C–160°C.

[0083] Those skilled in the art will understand that other modifications and variations can be made without departing from the spirit or scope of the invention. Because modifications, combinations, sub-combinations, and variations of the disclosed embodiments in conjunction with the spirit and essence of the invention may occur to those skilled in the art, the invention should be construed as encompassing all contents within the scope of the appended claims and their equivalents. The appended claims are incorporated in and form a part of this detailed description.

[0084] Those skilled in the art will also understand that, unless expressly stated otherwise, no method in this disclosure should be construed as requiring its steps to be performed in a particular order. Therefore, no particular order is intended to be inferred where a method claim does not actually describe the order in which its steps are followed, or where the claims or specification do not otherwise specifically state that the steps are limited to a particular order. Furthermore, if a method claim herein does not expressly describe a step mentioned in the foregoing description, it should not be assumed that such step is required by the claim.

Claims

1. A fiber optic connector assembly, comprising: A ferrule body comprising a polymer material, the ferrule body having a front end face, a rear end face, and a plurality of microchannels defined in the ferrule body and extending through the front end face; Multiple optical fibers extend through the ferrule body and terminate at the front end face, wherein each of the multiple optical fibers includes a stripped region, and the stripped region of each optical fiber extends through a corresponding microchannel among the multiple microchannels. as well as A thermoplastic adhesive material is disposed in the plurality of microchannels between the stripped areas of the plurality of optical fibers and the ferrule body, and configured to retain the plurality of optical fibers within the ferrule body, wherein the thermoplastic adhesive material has a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C.

2. The fiber optic connector assembly of claim 1, wherein the ferrule body further comprises a glass filler material mixed with the polymer material, wherein the ferrule body comprises at least 50% by weight of the glass filler material.

3. The fiber optic connector assembly according to claim 1 or 2, wherein the ferrule body comprises polyphenylene sulfide reinforced with glass-filled material.

4. The fiber optic connector assembly according to any one of claims 1 to 3, wherein: The insert body defines a groove that extends through the rear end face and is defined by an intermediate surface disposed between the front end face and the rear end face; The plurality of microchannels extend from the front end surface to the middle surface; The multiple optical fibers extend through the groove and through the rear end face; and The thermoplastic adhesive material is disposed in the groove between the plurality of optical fibers and the ferrule body.

5. The fiber optic connector assembly of claim 4, wherein each of the plurality of optical fibers further comprises an unstripped region, and at least a portion of the unstripped region is disposed in the groove of the ferrule.

6. The fiber optic connector assembly according to any one of claims 1 to 5, wherein the thermoplastic adhesive material comprises an adhesive polymer, said adhesive polymer being at least one selected from polyamide, polyurethane, polyolefin, ethylene-vinyl acetate, styrene block copolymer, polyester, copolyamide, or copolyester.

7. The fiber optic connector assembly of claim 1, wherein the thermoplastic adhesive material further comprises about 0.1 to about 10 parts by weight of at least one silane coupling agent per 100 parts by weight of the adhesive polymer.

8. The fiber optic connector assembly according to any one of claims 1 to 7, wherein the polymer material has a cold crystallization temperature lower than the melting point temperature of the thermoplastic adhesive material.

9. A fiber optic connector assembly, comprising: A ferrule body comprising a polymer material, the ferrule body having a front end face, a rear end face, and a plurality of microchannels defined in the ferrule body and extending through the front end face; Multiple optical fibers extend through the ferrule body and terminate at the front end face, wherein each of the multiple optical fibers includes a stripped region, and the stripped region of each optical fiber extends through a corresponding microchannel among the multiple microchannels. as well as A thermoplastic adhesive material is disposed in the plurality of microchannels between the stripped areas of the plurality of optical fibers and the ferrule body, and is configured to retain the plurality of optical fibers within the ferrule body. The ferrule body includes at least one of the following features (i) and (ii): (i) The crystallinity of the insert body at the first end face is different from that at the second end face; and (ii) At least some of the microchannels of the plurality of microchannels are arranged in a one-dimensional array, wherein the outermost microchannels of the one-dimensional array are spaced apart by a first distance at the front end face and by a second distance at the rear end face, wherein the second distance is smaller than the first distance.

10. The fiber optic connector assembly of claim 9, wherein the ferrule body further comprises a glass filler material mixed with the polymer material, and the ferrule body comprises at least 50% by weight of the glass filler material.

11. The fiber optic connector assembly of claim 9 or 10, wherein the ferrule body comprises polyphenylene sulfide reinforced with a glass-filling material.

12. The fiber optic connector assembly according to claim 9, wherein: The insert body defines a groove that extends through the rear end face and is defined by an intermediate surface disposed between the front end face and the rear end face; The plurality of microchannels extend from the front end surface to the middle surface; The multiple optical fibers extend through the groove and through the rear end face; and The thermoplastic adhesive material is disposed in the groove between the plurality of optical fibers and the ferrule body.

13. The fiber optic connector assembly of claim 12, wherein each of the plurality of optical fibers further comprises an unstripped region, and at least a portion of the unstripped region is disposed in the groove of the ferrule.

14. The fiber optic connector assembly according to any one of claims 9 to 13, wherein the thermoplastic adhesive material comprises an adhesive polymer, said adhesive polymer being at least one selected from polyamide, polyurethane, polyolefin, ethylene-vinyl acetate, styrene block copolymer, polyester, copolyamide, or copolyester.

15. The fiber optic connector assembly of claim 14, wherein the thermoplastic adhesive material further comprises about 0.1 to about 10 parts by weight of at least one silane coupling agent per 100 parts by weight of the adhesive polymer.

16. The fiber optic connector assembly according to any one of claims 9 to 15, wherein the polymer material has a cold crystallization temperature lower than the melting point temperature of the thermoplastic adhesive material.

17. A method for manufacturing an optical fiber connector assembly, the optical fiber connector assembly comprising a ferrule body and a plurality of optical fibers, the ferrule body comprising a polymer material, each of the plurality of optical fibers comprising a stripped region, the method comprising: Heating at least a portion of the ferrule body and providing a thermal gradient between a front end face and a rear end face of the ferrule body, wherein the front end face is at a lower temperature than the rear end face; as well as The stripped portions of the multiple optical fibers are inserted through the rear end face of the ferrule body into a plurality of microchannels defined in the ferrule body and extending through the front end face of the ferrule body, such that the stripped portions of the multiple optical fibers extend at least to the front end face. The stripped portions of the plurality of optical fibers extend through a molten thermoplastic adhesive disposed between the stripped portions of the optical fibers and the plurality of microchannels. The thermoplastic adhesive is cured in the plurality of microchannels between the stripped area of ​​the optical fiber and the ferrule body.

18. The method of claim 17, wherein the thermoplastic adhesive material has a Young's modulus of at least 100 MPa, a yield stress of at least 5 MPa, and a Shore A hardness of at least 80 at 25°C.

19. The method of claim 17 or 18, further comprising placing at least a portion of the ferrule body in thermal communication with a heating fixture, and the heating comprising heating the heating fixture and allowing heat to be conducted from the heating fixture to the at least a portion of the ferrule body.

20. The method of claim 19, wherein the heating of the heating fixture comprises induction heating.

21. The method of claim 19, wherein when at least a portion of the ferrule body is positioned in thermal communication with the heating fixture, the front end face of the ferrule body is exposed and does not contact the heating fixture.

22. The method of claim 21, wherein when at least a portion of the ferrule body is positioned in thermal communication with the heating fixture, the front portion of the ferrule body does not contact a portion of the heating fixture arranged in thermal communication with the rear portion of the ferrule body.

23. The method of claim 21 or 22, further comprising supplying a cooling medium to the front end face of the ferrule body during and / or after the heating of the at least portion of the ferrule body.

24. The method according to any one of claims 17 to 23, wherein the heating of at least a portion of the ferrule body is performed prior to the insertion of the stripped portions of the plurality of optical fibers.

25. The method of any one of claims 17 to 24, further comprising applying the thermoplastic adhesive material to the stripped portion of the plurality of optical fibers prior to the insertion of the stripped portion of the plurality of optical fibers.

26. The method according to any one of claims 17 to 25, wherein: The insert body defines a recess including a groove that extends through the rear end face and is defined by an intermediate surface disposed between the front end face and the rear end face; The plurality of microchannels extend from the front end face to the middle surface; and The method further includes supplying the thermoplastic adhesive material to the groove prior to the heating of at least a portion of the insert body.

27. The method of claim 26, wherein supplying the thermoplastic adhesive material to the groove of the insert body comprises: The monofilaments of the thermoplastic adhesive are positioned in the groove.

28. The method of claim 26, wherein supplying the thermoplastic adhesive material to the groove of the insert body comprises: Molten thermoplastic adhesive is dispensed into the groove.

29. The method of claim 28, wherein the molten thermoplastic adhesive remains in a molten form before and during the heating of at least a portion of the insert body.

30. The method of claim 28, further comprising: Before heating at least a portion of the insert body, the molten thermoplastic adhesive is solidified, wherein the heating causes the thermoplastic adhesive to remelt into a molten form.

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