Bridge with hinged covers to hold an FAU in a receptacle for co-packaged optics

Abstract

A system is disclosed for securing fiber array units (FAUs) in receptacles using a bridge and a series of hinged covers. The bridge is positioned above and spans across multiple receptacles. Each cover is hingedly coupled to the bridge and, in a closed position, latches to a beam disposed below and in front of the receptacles to apply a downward force that holds a corresponding FAU securely in its receptacle. The covers are individually operable so that a single FAU can be inserted or removed without disturbing neighboring FAUs. A corresponding bridge structure includes a rear wall with cover receiving areas, a front wall with catch elements and recesses for engaging cover prongs, sidewalls, and medial elements configured to support the receptacles while allowing the bridge to float around other frame elements, thereby providing a compact, reworkable FAU retention architecture suitable for high-density optical packaging.

Description

Attorney Docket No.: HI24-013PCTBRIDGE WITH HINGED COVERS TO HOLD AN FAU IN A RECEPTACLE FOR CO-PACKAGED OPTICSPRIORITY APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Application Serial No. 63 / 725,047 filed November 26, 2024, the content of which is relied upon and incorporated herein by reference in its entirety.BACKGROUND

[0002] The present disclosure generally relates to bridges for co-packaged optics applications and related components, methods and systems.

[0003] The field of Silicon Photonics (SiP) has been in development for several years. Some products have been commercialized and more are under active development. In the field of SiP, silicon is used as the optical medium, primarily in the near infrared (NIR) wavelength band around wavelengths of 1.31 pm and 1.55 pm, which are used in telecommunications. Some advantages of SiP are the possibilities to use existing semiconductor fabrication methods and infrastructure and the integration of electronics and photonics into a single chip as photonic integrated circuits (PICs) or at least into components that work closely together.

[0004] One issue that has not yet been fully addressed in the field of SiP is injecting or extracting light into / out of SiP chips. In telecommunications, light is usually transported in fibers, which now have to be coupled to the SiP PICs. Here, three methods can be distinguished. The first, edge coupling, during which waveguides of the SiP chip end are interfaced with at the edge (side) of the SiP chip. The second grating coupling, during which the PICs use grating couplers as an interface, where the light path is close to perpendicular to the surface of the chip. Grating couplers can be located anywhere on the chip’s surface. And the third is evanescent coupling. For evanescent coupling, the waveguide in the silicon is brought into close proximity with a glass waveguide so that the light can couple evanescently from the silicon to the glass and vice versa.

[0005] One of the difficulties with coupling light to SiP PICs is the difference in mode field diameters. Single mode fibers have a mode field diameter of about 10 pm, while modes in silicon waveguides may be of submicron dimensions because of the largeAttorney Docket No.: HI24-013PCT refractive index of silicon (about 3.5), which leads to high losses if the fibers are coupled directly to the SiP waveguides. To reduce these losses, mode converters are required to scale the modes of the SiP to the size of the fiber modes.

[0006] While grating couplers can be designed such that they easily couple to single mode fibers, they have a limited bandwidth, so that they cannot support many different wavelengths (e.g., for WDM applications). Also, the fiber orientation perpendicular to the surface of the chip poses limits on the geometry / arrangements, in which these chips may be used.

[0007] Edge couplers require separate mode field converters to be able to couple to fibers. These may be realized in the silicon, as an additional interposer chip, where the conversion is realized through changing the waveguide size along the length, or through imaging optics.

[0008] With the evanescent coupling, the mode field conversion can already be built into the geometry of the glass waveguides, to which fibers may then directly be coupled.

[0009] For these reasons, among others, there is a need for improved products and coupling methods in the field of SiP for co-packaged optics applications.SUMMARY

[0010] Disclosed herein are various embodiments of components, assemblies, methods and systems for co-packaged optics applications. Particularly, embodiments disclosed herein relate to components, assemblies, methods and systems configured to hold fiber array units (“FAUs”) in receptacles. One embodiment relates to a mechanism for holding a fiber array unit (FAU) securely in a receptacle by locating a bridge above multiple receptacles with a series of hinged covers that latch to a beam below and in front of the receptacles. The covers provide a downward force to the FAU by means of a soft pad attached to the FAU so that the FAU remains aligned with the receptacle. The bridge and covers are arranged so that individual FAUs can be inserted into or extracted from their receptacles without interfering with other FAUs. In typical use, the receptacles are associated with photonic integrated circuits, which are integrated circuits that guide and process light using on-chip optical waveguides and related optical devices fabricated on a semiconductor substrate.Attorney Docket No.: HI24-013PCT

[0011] According to another aspect, the FAU includes an upper FAU element, a lower FAU element, and a microlens array. The upper FAU element includes centrally located v- grooves for positioning or holding one or more fibers and end v-grooves that may be used for positioning alignment elements such as rods or pins. Exemplary FAUs suitable for use with the disclosed mechanism are described in existing FAU patents, which are incorporated by reference.

[0012] According to another aspect, a soft, compliant pad can be attached to the FAU and configured to transfer the force of a hinged lid or cover to the FAU so that it remains aligned to a receptacle. The desired force is about 100 gf. Such compliant pads are typically used as heat transfer elements in electronics and are suitable for the high temperatures seen in circuit boards. They are made from compliant materials and are available in different thicknesses and stiffnesses to allow tuning of compressive forces. The pad is preferably configured to have enough resilience to accommodate deflection and to minimize impact on the optical path. In alternative embodiments, a spring system, such as a leaf spring, can be used instead of the pad.

[0013] Multiple options are disclosed for holding FAUs in a receptacle, with the receptacle preferably positioned early in a manufacturing process, for example before solder reflow, and the holding devices placed later in the manufacturing process, for example after solder reflow. Some embodiments include a frame assembly configured for coupling to a photonic integrated circuit. Multiple frame assemblies can be coupled to multiple photonic integrated circuits to create a tandem or quad-like structure. Some embodiments further include a bridge coupled to a strain relief system and configured to span across multiple photonic integrated circuits. The bridge is preferably configured to hold multiple individually addressable FAUs without directly contacting the photonic integrated circuits.

[0014] According to another aspect, a frame assembly is configured to receive an FAU in a receptacle. The frame assembly includes a cover coupled to a base by a hinge. The cover has an upper surface, a lower surface spaced from the upper surface by a cover thickness, a front surface, a rear surface, and cover sides. Prongs extend from the lower surface and are arranged to engage portions of the base when the cover is moved downward. The base includes a base body with an upwardly extending base wall, lateral base arms,Attorney Docket No.: HI24-013PCT and downwardly extending base extensions that form a structure configured to catch the prongs of the cover. A front base element extends between the base extensions to form a step that cooperates with the prongs to provide a latch. The base can include an FAU receiving area or receptacle configured to receive and align an FAU, and a platform can be provided to support a photonic integrated circuit and a portion of the frame assembly.

[0015] According to yet another aspect, an FAU is placed manually or robotically into the receptacle so that its alignment features contact corresponding alignment features in the receptacle. Fibers coupled to the FAU can be routed to a strain relief system for strain relief. When the cover is closed, it compresses the soft pad attached to the FAU so that a force of about 100 gf is exerted on the FAU. The cover is latched to the base by the prongs and can be opened either by pulling or elongating the cover or by using a separate tool that disengages the prongs at a latching point. The cover can also include a flexure opening or area, preferably configured as an elongated slot, such that the cover is configured to snap into place when inserted into the base.

[0016] According to yet another aspect, a frame system includes a series of frame assemblies and a strain relief system. FAUs are positioned within the frame assemblies and fibers coupled to the FAUs are positioned within the strain relief system. The strain relief system can include a stiffener bar that extends across a portion of the structure and is configured for mounting onto a perimeter element. The stiffener bar can include a plurality of ridges that are paired to support fibers such that there is a fiber receiving area between a pair of ridges. Mounting holes in the stiffener bar receive fastening elements that cooperate with stiffener lids having complementary apertures. The stiffener lids clamp the fibers in the fiber receiving areas to provide strain relief.

[0017] According to yet another aspect, a, a frame system includes a cover system having a plurality of covers and an attachment mechanism, and a bridge. The covers of the cover system can be substantially similar to the covers of the frame assembly. Each cover has an upper and lower surface, a front and rear surface, and sides, with prongs extending from the lower surface. The prongs are configured to engage the bridge when the cover is moved downward. Rear portions of the covers are coupled to the bridge, preferably by hinges. The attachment mechanism is configured to facilitate positioning of multiple covers onto the bridge and may be elongated so that its width substantially matches the width of aAttorney Docket No.: HI24-013PCT rear bridge wall. The attachment mechanism can be coupled to the bridge by mechanical or chemical methods, such as press-fit or adhesive, and can include cover receiving areas that abut rear portions of the covers.

[0018] According to yet another aspect, a bridge includes various alignment features that facilitate coupling to an FAU receiving area or receptacle having a complementary structure that allows an FAU to fit partially or fully within the receptacle. Alignment features can include grooves, planar surfaces, notches, or other mechanical features configured to facilitate alignment with an FAU or receptacle. The bridge preferably includes elements configured not to touch photonic integrated circuits or receptacles, but rather to float around other parts of the frame system. The bridge can include a rear bridge wall with cover receiving areas and apertures for coupling to other components, bridge sidewalls coupled to the rear bridge wall, a front bridge wall extending between the sidewalls and including catch elements and recesses configured to engage prongs of the covers, and medial bridge elements extending between the rear and front bridge walls and configured to support receptacles. Outer profiles of the medial bridge elements can complement the bottom profiles of the receptacles.

[0019] The bridge can further include a strain relief beam having a front beam section that acts as a stiffener bar and side beam sections. The front beam section can include ridges that are paired to support fibers such that there is a fiber receiving area between a pair of ridges, and mounting holes configured to receive fastening elements that cooperate with stiffener lids having complementary apertures. The strain relief beam can be integral with the bridge sidewalls or coupled to the sidewalls by mechanical means. The bridge can be constructed of machined or stamped metal or molded plastic and is preferably configured to maximize stiffness while minimizing vertical height. Multiple bridges can be attached in proximity to form larger arrays, with corners configured so they do not interfere or collide.

[0020] According to yet another aspect, a frame system includes the bridge and a cover having an elongated main cover portion that extends past the front bridge wall for coupling with a front beam section that acts as a stiffener bar. Prongs of this cover are configured to engage a rear wall of the front beam section when the cover is moved downward, while the rear portion of the cover is coupled to the bridge by a hinge.Attorney Docket No.: HI24-013PCT

[0021] According to yet another aspect, a mechanical tool can be provided for unlatching the covers. The tool includes a handle and cover receiving arms having a slot defined therein. The slot has an interior profile with a shape complementary to the outer shape of a cover. When the slot engages a cover, movement of the handle causes deformation or displacement of the cover sufficient to disengage its prongs from the bridge or beam.

[0022] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0023] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments, and together with the description serve to explain principles and operation of the various embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 illustrates a fiber array unit (FAU) assembly for positioning within various assemblies and systems in accordance with embodiments disclosed herein;

[0025] FIGs. 2A and 2B illustrate a frame assembly in accordance with embodiments disclosed herein;

[0026] FIGs. 3, 4 and 5 illustrate mounting of an FAU assembly in a frame assembly in accordance with embodiments disclosed herein;

[0027] FIG. 6 illustrates how various elements of a frame assembly, including receptacles and a stiffener bar can mount to a board during reflow in accordance with embodiments disclosed herein;

[0028] FIGs. 7 and 8 illustrates how various elements of a frame assembly, including covers, can mounted to a board after reflow in accordance with embodiments disclosed herein;Attomey Docket No.: HI24-013PCT

[0029] FIG. 9 is an isometric view of a frame system, including a bridge, in accordance with embodiments disclosed herein;

[0030] FIG. 10A is an isometric view of a bridge coupled to a board in accordance with embodiments disclosed herein;

[0031] FIG. 10B is a side cross-sectional view of a bridge in accordance with embodiments disclosed herein;

[0032] FIG. 11 illustrates an overview of bridges attached to a board in accordance with embodiments disclosed herein;

[0033] FIG. 12 schematically illustrates how a bridge can be coupled to a receptacle and covers in accordance with embodiments disclosed herein;

[0034] FIG. 13 illustrates a frame system, including a bridge, in accordance with embodiments disclosed herein;

[0035] FIGs. 14 and 15 illustrate a bridge in accordance with embodiments disclosed herein;

[0036] FIG. 16 illustrates shows an alternative design for the latching of the covers in accordance with embodiments disclosed herein; and

[0037] FIG. 17 illustrates a mechanical tool for unlatching covers in accordance with embodiments disclosed herein;

[0038] The figures are not necessarily to scale. Like numbers used in the figures may be used to refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the disclosure will now be described with particular reference to the drawings. Exemplary embodiments of the present disclosure may take on various modifications and alterations without departing from the spirit and scope of the disclosure. Accordingly, it is to be understood that the embodiments of the presentAttorney Docket No.: HI24-013PCT disclosure are not to be limited to the following described exemplary embodiments, but are to be controlled by the features and limitations set forth in the claims and any equivalents thereof.

[0040] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0041] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0042] Spatially related terms, including but not limited to, “lower,” “upper,” “beneath,” “below,” “above,” and “on top,” if used herein, are utilized for ease of description to describe spatial relationships of an element(s) to another. Such spatially related terms encompass different orientations of the device in use or operation in addition to the particular orientations depicted in the figures and described herein. For example, if an object depicted in the figures is turned over or flipped over, portions previously described as below or beneath other elements would then be above those other elements.

[0043] Cartesian coordinates are used in some of the Figures for reference and are not intended to be limiting as to direction or orientation.

[0044] For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “top,” “bottom,” “side,” and derivatives thereof, shall relate to the disclosure as oriented with respect to the Cartesian coordinates in the corresponding Figure, unless stated otherwise. However, it is to be understood that the disclosure may assume various alternative orientations, except where expressly specified to the contrary.

[0045] For the purposes of describing and defining the subject matter of the disclosure it is noted that the terms “substantially” and “generally” may be utilized herein toAttorney Docket No.: HI24-013PCT represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation.

[0046] The present disclosure relates to a SiP chip using lensed grating couplers, i.e., the grating couplers are not intended to interface directly with fibers, but instead generate a nearvertical expanded beam for coupling. The present disclosure further relates to a system that holds an FAU securely in the receptacle by locating a bridge above multiple SiP chips with a series of hinged covers that latch to a beam below and in front of the chips. The covers provide a downward force to the FAU by means of a soft pad attached to the FAU. The bridge is designed such that individual FAUs may be inserted into or extracted from the receptacles without interfering with the other FAUs.

[0047] FIG. 1 shows an embodiment of an FAU assembly 100 with a compliant pad 130 attached. The compliant pad 130 is configured to transfer the force of a hinged lid to the FAU so that it remains aligned to a receptacle, as will be further described. The desired force is about100 gf. Such compliant pads are typically used to as heat transfer elements in electronics and are suitable for the high temperatures seen in circuit boards. They are made from compliant materials, and are available in different thicknesses and stiffnesses to allow tuning of compressive forces. The compliant pad is preferably configured to have enough resilience to accommodate deflection, and minimize impact on optical path. Alternatively, a spring system, comprising a leaf spring, for example, could be used instead.

[0048] The FAU assembly 100 further includes an upper FAU element 110, a lower FAU element 120, and a microlens array 140. The upper FAU element 110 includes a plurality of centrally-located v-grooves 112 disposed therein for positioning or holding one or more fibers F. The upper FAU element additionally includes two end v-grooves 114a, 114b, which may be used for positioning of alignment elements such as rods or pins 150a, 150b, for example. Exemplary FAUs and FAU assemblies are shown and described, inter alia, in US PatentNos. 10,942,316, 11,194,107, 11,586,000, 11,567,285, and 11,415,753, which are incorporated herein by reference.

[0049] As shown in the following figures, multiple options are disclosed for holding FAUs and / or FAU assemblies in a receptacle, with the receptacle preferably having been positioned early in a manufacturing process (i.e. before solder reflow) and the holding devicesAttorney Docket No.: HI24-013PCT preferably having been placed later in the manufacturing process (i.e. after solder reflow). Some embodiments disclosed herein generally include a frame assembly configured for coupling to a PIC. Alternatively or in addition to, multiple frame assemblies could be coupled to multiple PICs to create a tandem or quad-like structure. Some embodiments further include a bridge coupled to a strain relief system configure to span across multiple PICs. This type of bridge is preferably configured to hold multiple individually addressable FAUs or FAU assemblies without directly contacting the PICs.

[0050] FIGs. 2A, 2B, 3 and 4 show one embodiment of a frame assembly 200, configured to receive an FAU or FAU assembly, positioned on and coupled to a board B. This particular embodiment of the frame assembly 200 is characterized by a cover 210 coupled to a base 260 via a hinge 212 or a similar coupling element. In this embodiment, the cover 210 is configured for coupling both a receptacle for the FAU / FAU assembly and / or a PIC (CTE considerations may require an approximate match of material CTEs or a flexible attachment), as shown particularly in FIG. 6. In some embodiments, the frame assembly can be configured to use an area of the PIC outboard of a glass receptacle, which may be typically reserved for adhesive overflow. The frame assembly 200 thus includes a cover 210, a base 260 coupled to the cover 210, and a receptacle 290 is coupled to the base 260. In some embodiments, a platform 280 is also configured to support the PIC and a portion of the frame assembly 200. Here, the base 260 is coupled to the cover 210 by a hinge 212, although other coupling methods are contemplated.

[0051] The cover 210 includes a main cover portion 220, having an upper cover surface 222, a lower cover surface 224 positioned a distance away from the upper cover surface by a cover thickness Ct, a front cover surface 226, and a rear cover surface 228. Extending from the lower cover surface 224 is a plurality of prongs 230a, 230b coupled to cover sides 232a, 232b. The plurality of prongs 230a, 230b is configured to engage the base 260 when the cover is moved downwardly. One or more rear portions 235 of the cover 210 is coupled to the base 260, preferably by the hinge 212.

[0052] The base 260 includes a base body 262, including an upwardly extending base wall 264, lateral base arms 270a, 270b coupled to the base wall 264, and a downwardly extending base extensions 276a, 276b coupled to each base arm. The base 260 is configured to include a plurality of alignment features that facilitate coupling of the frame assembly 200 to theAttorney Docket No.: HI24-013PCTFAU, using an FAU receiving area or receptacle 290 coupled to the base 260. Alignment features can include grooves, planar surfaces, notches, or any other mechanical features that could be configured to facilitate alignment with one or more components of an FAU or FAU assembly. Accordingly, the embodiments disclosed herein should not be construed as limiting.

[0053] Referring particularly to FIGs. 2A and 7, the upwardly extending base wall 264 includes a cutout area 265 formed by a rear cutout wall 266, a bottom cutout wall 267, and cutout sidewalls 268a, 268b. In some configurations, the lateral base arms 270a, 270b extend laterally and outwardly from the base wall 264 to form lateral protrusions 272a, 272b. Extending downwardly from each lateral base arm 270a, 270b is a base extension 276a, 276b. A front base element 278 extends between base extensions 276a, 276b to form a front base step 279. Together, lateral protrusions 272a, 272b, base extensions 276a, 276b, the front base element 278, and the front base step 279 are configured to catch prongs 230a, 230b of the cover 210, as particularly shown in FIG. 4. Variations of the frame assembly may span multiple PICs at a time (See, FIG. 8, e.g.). Accordingly, the embodiments shown in FIGs. 2A, 2B, 3, and 4 are representative.

[0054] FIGs. 3 and 4 schematically illustrate the positioning of the FAU or FAU assembly 100 in the receptacle 290. The FAU assembly 100 is preferably placed manually or robotically so that the alignment features that align the FAU or FAU assembly to the receptacle are in contact. Upon assembly, the fibers F may be coupled to a strain relief system 600 for strain relief. FIGs. 3 and 4 further illustrate the FAU assembly 100 in the receptacle 290 after placement with the cover 210 in an open position and in a closed position. The closed cover 210 compresses the compliant pad 130, so that a force of about 100 gf is exerted on the FAU assembly 100. The cover 210 is preferably configured to latch to the base 260, via the plurality of prongs 230a, 230b, e.g., and may be opened either by a pulling or elongation of the cover or by using a separate tool that disengages the plurality of prongs 230a, 230b from the lid at a latching point. The cover can also be configured to include a flexure opening / area 216 such that the cover is configured to snap into place when inserted into the base 260. The flexure opening / area 216 is preferably configured as an elongated slot in the cover 210, as particularly shown in FIGs. 4 and 5.Attorney Docket No.: HI24-013PCT

[0055] FIG. 5 shows a frame system 300, including a series of frame assemblies 200 and a strain relief system 600. An FAU assembly 100 is positioned within the frame assembly 200. A section of fibers F (which could also be ribbon fiber) coupled to the FAU assembly 100 are positioned within the strain relief system 600. The strain relief system 600 includes a stiffener bar 620 that extends across a portion of the board B. The stiffener bar 620 is configured for mounting onto a perimeter element 700, which is coupled to the board B. FIGs. 6, 7, and 8 show additional detail of the stiffener bar 620. The stiffener bar 620 includes a plurality of ridges 622 that are paired to support a plurality of fibers F such that there is a fiber receiving area 624 between a pair of ridges 626. The stiffener bar 620 also includes mounting holes 628 configured to receive a fastening element 630 disposed in stiffener lids 640, having complementary apertures 642 configured for positioning of the fastening elements 630.

[0056] FIGs. 6, 7, and 8 illustrate how elements of the frame system 300 and the strain relief system 600 can be mounted to the board B during various stages. FIG. 6 illustrates how the PIC, receptacles 290, the stiffener bar 620, and the perimeter element 700 can be mounted to the board B during reflow. The FAU receiving area or receptacle 290 is configured to have a complementary structure, such as a u-shape, which allows for the FAU assembly to fit partially or fully within the FAU receiving area or receptacle 290 and also complement the shape of the base 260, as shown particularly in FIG. 6. FIGs. 7 and 8 illustrate how the cover 210 and the base 260 could be added to the overall assembly / system after reflow.

[0057] FIGs. 9, 12, and 13 illustrate an embodiment of a frame system 1000, including a cover system 800, having a plurality of covers 810 and an attachment mechanism 880, and a bridge 900. Referring particularly to FIG. 9, the cover 810 included in the cover system 800 is substantially similar to the cover 210 included in the frame assembly 200. The cover 810 thus includes a main cover portion 820, having an upper cover surface 822, a lower cover surface 824 positioned a distance away from the upper cover surface by a cover thickness Ct2, a front cover surface 826, and a rear cover surface 828. Extending from the lower cover surface 824 is a plurality of prongs 830a, 830b coupled to cover sides 832a, 832b. The plurality of prongs 830a, 830b is configured to engage the bridge 900 when the cover 810 is moved downwardly. One or more rear portions 835 of the cover 810 is coupled to bridge 900, preferably by a hinge 812. The attachment mechanism 880 is configured to facilitateAttorney Docket No.: HI24-013PCT positioning of a plurality of covers 810 onto the bridge 900. The attachment mechanism 880 is elongated such that its width is the substantially same width of the rear bridge wall 910. The attachment mechanism 880 may be coupled to the bridge by a mechanical and / or chemical methods. For example, the attachment mechanism 880 may be press fit to the bridge and / or adhesively coupled to the bridge. The attachment mechanism 880 includes a plurality of cover receiving areas 882 that abut rear portions 835 of the covers 810.

[0058] Referring particularly to FIG. 10 A, 10B, 11, and 12, the bridge 900 includes various alignment features that facilitate coupling to the FAU assembly and an FAU receiving area or receptacle 890, having a complementary structure that allows for the FAU assembly to fit partially or fully within the FAU receiving area or receptacle 890. Such alignment features can include grooves, planar surfaces, notches, or any other mechanical features that could be configured to facilitate alignment with one or more components of an FAU or FAU assembly and / or a receptacle. Moreover, the bridge 900 preferably includes a plurality of elements configured to not touch PICs or receptacles, but rather float around other parts of the frame system.

[0059] Referring particularly to FIGs. 10A and 10B, the bridge 900 is shown positioned on a plurality of platforms 280 and a portion of a board B. FIG. 10A is an isometric view, while FIG. 10B is a side view, further illustrating a section of the bridge 900 and the u-shaped profile of the cover receiving areas 914. The bridge 900 includes a rear bridge wall 910, bridge sidewalls 920, a plurality of medial bridge elements 930, a front bridge wall 940 and a strain relief beam 950.

[0060] The rear bridge wall 910 includes a plurality of cover receiving areas 914 disposed therein and at least two apertures 915 configured for coupling to other components (not shown). Coupled to each end of the rear bridge wall 910 is a bridge sidewall 920. Each bridge sidewall 920 is coupled to the front bridge wall 940 and the strain relief beam 950.

[0061] The bridge sidewalls 920 are preferably integrated with respective ends 922 of the rear bridge wall 910, and extend a distance beyond the overall length of the rear bridge wall 910 to form a stepped sidewall section 912, as shown particularly in FIG. 10 A. Each bridge sidewall 920 is integrated with the front bridge wall 940.Attorney Docket No.: HI24-013PCT

[0062] The front bridge wall 940 extends between the bridge sidewalls 920 and includes a plurality of catch elements 924 and inner recesses 926, and outer recesses 927 configured to engage with prongs 830a, 830b of the covers 810, as shown particularly in FIGs. 12 and 13.

[0063] The plurality of medial bridge elements 930 extend from the rear bridge wall 910 to the front bridge wall 940. The medial bridge elements 930 are configured to support the receptacles 290, as particularly shown in FIG. 12. According, outer profiles of each medial bridge element 930 complements the bottommost profiles of the receptacle 290.

[0064] Referring back to FIG. 10A, the strain relief beam 950 of the bridge 900 includes a front beam section 952, which acts as a stiffener bar, and side beam sections 954a, 954b. The front beam section 952 includes a plurality of ridges 956 that are paired to support a plurality of fibers F such that there is a fiber receiving area 958 between a pair of ridges 956. The front beam section also includes mounting holes 957 configured to receive a fastening element 630 disposed in stiffener lids 640, having complementary apertures 642 configured for positioning of fastening elements 630.

[0065] The strain relief beam 950 may be configured to be integral with the bridge sidewalls 920 or coupled to the bridge sidewalls 920 by mechanical means such as screws, for example.

[0066] The various elements of the bridge 900 may be constructed of machined or stamped metal or molded plastic. In preferred embodiments, the bridge is configured to maximize the moment of inertia to make it as stiff as possible, thereby resisting upward deflection, while minimizing the vertical height of the bridge. FIG. 11 shows an overview of how multiple bridges (two being shown) can be attached to a board. Here, respective comers of the bridges are configured such that they do not interfere or collide when positioned on the board. FIG. 12 schematically shows an FAU assembly being placed in the receptacle and bridge. FIG. 13 shows an FAU assembly with a bridge and a strain relief system. FIG. 14 and FIG. 15 illustrate a bridge with and without covers attached to the stiffener element.

[0067] FIG. 16 illustrates another embodiment of a frame system 1800, including the bridge 900 and a cover 1810 having an elongated main cover portion 1820, which extends past the front bridge wall 940 for coupling with the front beam section 952 (i.e. the stiffener bar). Specifically, prongs 1830a, 1830b are configured to engage with a rear wall 960 of theAttorney Docket No.: HI24-013PCT front beam section 952. The cover 1810 further includes an upper cover surface 1822, a lower cover surface 1824 positioned a distance away from the upper cover surface by a cover thickness Ct3, a front cover surface 1826, and a rear cover surface 1828. Extending from the lower cover surface 1824 is the plurality of prongs 1830a, 1830b coupled to cover sides 1832a, 1832b. The plurality of prongs 1830a, 1830b is thus configured to engage the front beam section 952 of the bridge 900 when the cover 1810 is moved downwardly. One or more rear portions 1835 of the cover 1810 is coupled to bridge 900, preferably by a hinge 1812.

[0068] FIG. 17 illustrates an embodiment of a mechanical tool 1100 for unlatching the covers 810. The tool 100 includes a handle 1150 and cover receiving arms 1170, 1172, having a slot 1174 defined therein. The slot 1174 has an interior tool profile 1176 with a shape complementary to the outer shape of the cover 810.

[0069] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosure. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the embodiments disclosed herein should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

Attorney Docket No.: HI24-013PCTClaimsWhat is claimed is:

1. An assembly comprising: a plurality of receptacles; a plurality of FAUs, each FAU being received in a corresponding one of the receptacles; a bridge located above and spanning across at least two of the receptacles; and a series of covers hingedly coupled to the bridge, each cover being movable between an open position and a closed position and being configured, in the closed position, to latch to a beam disposed below and in front of the receptacles; wherein, in the closed position of each cover, the cover is configured to provide a downward force to the FAU received in the corresponding receptacle so that the FAU is held securely in the receptacle; and wherein the bridge and the series of covers are configured such that an individual FAU can be inserted into or extracted from its receptacle by operating only a corresponding one of the covers without interfering with other FAUs.

2. The assembly of claim 1, wherein the downward force provided by each cover to the corresponding FAU in the closed position is about 100 gf.

3. The assembly of claim 1 or claim 2, wherein at least one of the covers comprises a flexure opening in the form of an elongated slot configured such that the cover snaps into place when inserted into engagement with a latch.

4. The assembly of any one of claims 1 to 3, wherein at least one of the FAUs comprises: an upper FAU element having centrally located v-grooves configured to position or hold a plurality of fibers; a lower FAU element; a microlens array; and alignment features configured to cooperate with complementary alignment features of the corresponding receptacle.Attorney Docket No.: HI24-013PCT5. The assembly of any one of claims 1 to 4, wherein the upper FAU element further comprises end v-grooves configured to receive rods or pins that align the FAU to the receptacle.

6. The assembly of any one of claims 1 to 5, further comprising a frame assembly including a cover and a base coupled by a hinge, the base including a wall and lateral base arms with downwardly extending extensions and a front base element forming a step configured to catch prongs of the cover when the cover is moved downward.

7. The assembly of claim 6 or of any one of claims 1 to 5, wherein the cover of the frame assembly comprises a main cover portion having an upper surface, a lower surface spaced from the upper surface by a cover thickness, front and rear surfaces, cover sides, and prongs extending from the lower surface and configured to engage the base.

8. The assembly of any one of claims 1 to 7, further comprising a strain relief system including a stiffener bar having a plurality of ridges that are paired to support fibers coupled to the FAUs such that there is a fiber receiving area between a pair of ridges, and mounting holes configured to receive fastening elements that cooperate with stiffener lids having apertures to clamp the fibers in the fiber receiving areas.

9. The assembly of any one of claims 1 to 8, wherein the bridge is configured to hold multiple individually addressable FAUs without directly contacting the receptacles.

10. A bridge for securing a plurality of FAUs in respective receptacles, the bridge comprising: a rear bridge wall having a plurality of cover receiving areas; a front bridge wall spaced from the rear bridge wall and including catch elements and recesses configured to engage prongs of covers; bridge sidewalls coupled to the rear bridge wall and the front bridge wall; and medial bridge elements extending between the rear bridge wall and the front bridge wall and configured to support a plurality of receptacles each configured to receive an FAU; wherein the bridge is configured to float around other parts of a frame system such that the bridge does not directly touch the receptacles.Attorney Docket No.: HI24-013PCT11. The bridge of claim 10, further comprising an attachment mechanism coupled to the rear bridge wall and elongated such that its width is substantially the same as a width of the rear bridge wall, the attachment mechanism having cover receiving areas that abut rear portions of a plurality of covers and facilitate positioning of the covers onto the bridge.

12. The bridge of claim 10 or claim 11, wherein the cover receiving areas of the rear bridge wall have a generally U-shaped profile and the front bridge wall includes inner and outer recesses in which the catch elements are disposed.

13. The bridge of any one of claims 10 to 12, wherein outer profiles of the medial bridge elements complement bottom profiles of the receptacles so that the medial bridge elements support the receptacles.

14. The bridge of any one of claims 10 to 13, further comprising a strain relief beam including a front beam section acting as a stiffener bar and side beam sections, the front beam section having ridges that are paired to support fibers such that there is a fiber receiving area between a pair of ridges.

15. The bridge of claim 14 or of any one of claims 10 to 13, wherein the front beam section includes mounting holes configured to receive fastening elements disposed in stiffener lids having complementary apertures for positioning the fastening elements.

16. The bridge of any one of claims 10 to 15, wherein the strain relief beam is integral with the bridge sidewalls.

17. The bridge of any one of claims 10 to 16, wherein the bridge is constructed of machined or stamped metal or molded plastic and is configured to maximize stiffness while minimizing vertical height.

18. The bridge of any one of claims 10 to 17, wherein multiple bridges are configured such that respective comers of the bridges do not interfere or collide when the bridges are positioned adjacent one another.

19. The assembly of any one of claims 1 to 9, further comprising a mechanical tool for unlatching at least one of the covers, the mechanical tool comprising a handle and coverAttorney Docket No.: HI24-013PCT receiving arms having a slot defined therein, the slot having an interior profile with a shape complementary to an outer shape of one of the covers.

20. The assembly of claim 19, wherein the slot is dimensioned such that, when the slot engages a selected cover and the handle is moved, the cover is deformed or displaced sufficiently to disengage its prongs from the bridge or the beam without disturbing adjacent covers.

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