Expanded beam co-packaged optics assemblies

Abstract

Co-packaged optics assemblies for are disclosed. The assemblies include a connector assembly configured to provide a high-density interface, and a receptor assembly coupled to the connector assembly. The disclosed concepts provide improved angular and lateral alignment through the arrangement of pins, latches, snaps and other alignment features. Additional aspects of the co-packaged optics assemblies disclosed herein include enhanced coarse alignment and sealing of the optical path to protect from environmental contaminants. These co-packaged optics assemblies enable low-loss, scalable, and reliable coupling between photonic integrated circuits (PICs) and fiber arrays, facilitating next-generation co-packaged optics systems.

Description

Attorney Docket No.: HI24-113PCT EXPANDED BEAM CO-PACKAGED OPTICS ASSEMBLIES PRIORITY INFORMATION

[0001] This application claims the benefit of priority of U.S. Application Serial Nos. 63 / 702,161 filed October 2, 2024, and 63 / 725,254 filed November 26, 2024. The content of each aforementioned priority application is relied upon and incorporated herein by reference in its entirety. BACKGROUND

[0002] The present disclosure generally relates to expanded beam co-packaged optics assemblies, including receptor assemblies and connector assemblies for co-packaged optics applications.

[0003] The field of Silicon Photonics (SiP) has been in development for several years and some products have been commercialized and more are under active development. In SiP silicon is used as the optical medium, primarily in the near infrared (NIR) wavelength band around wavelengths of 1.31 μm and 1.55 μm, which are used in telecommunications.

[0004] Some advantages of silicon photonics (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 (alternatively “PICs”) or at least into components that work closely together.

[0005] One of the problems that has not yet been finally solved is a method of injecting or extracting light into / out of the 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.

[0006] 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 μm, whileAttorney Docket No.: HI24-113PCT modes in silicon waveguides may be of submicron dimensions because of the large 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] For these reasons, among others, there is a need for improved connectors for co-packaged optics applications. SUMMARY

[0011] Disclosed herein are various embodiments of co-packaged optics assemblies, including related features, components, methods and systems.

[0012] The assemblies include a connector assembly configured to provide a high-density interface, and a receptor assembly coupled to the connector assembly. The disclosed concepts provide improved angular and lateral alignment through the arrangement of pins, latches, snaps and other alignment features. Additional aspects of the co-packaged optics assemblies disclosed herein include enhanced coarse alignment and sealing of the optical path to protect from environmental contaminants. These co-packaged optics assemblies enable low-loss, scalable, and reliable coupling between photonic integrated circuits (PICs) and fiber arrays, facilitating next-generation co-packaged optics systems.Attorney Docket No.: HI24-113PCT

[0013] According to one aspect of the disclosure, a co-packaged optics assembly is configured to provide a high-density interface of at least 2x40 channels. Some configurations of the connector include two portions, one of which is permanently attached to a photonic integrated circuit (PIC). This receptor assembly provides microlens arrays on the front and back to create expanded optical beams and the optical turn to interface with the expanded beam of the PIC. The connector assembly provides an expanded beam on one side and fiber connectivity on the other side.

[0014] Another aspect of the disclosure relates to a two-part fiber-to-PIC alignment method. The first part is an FAU with a prism and microlens array (MLA) on one side and a microlens array (MLA) on the other side, enclosed in a housing structure. The first stage is attached permanently to the PIC. The second stage includes a corresponding MLA, and a FAU.

[0015] The concepts disclosed herein provide improved angular (and lateral) alignment through the arrangement of the pins (symmetric with respect to one or more axes), or through alignment features in the glass connector, improved coarse alignment and latching (using, e.g. snaps), and sealing of the optical path from the environment.

[0016] 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.

[0017] 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

[0018] FIG.1 schematically illustrates an isometric view of an embodiment of a co- packaged optics assembly in accordance with embodiments disclosed herein;Attorney Docket No.: HI24-113PCT

[0019] FIG.2 schematically illustrates a side view of an embodiment of a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0020] FIGs.3 and 4 schematically illustrate 2D arrangements of optical fibers in accordance with embodiments disclosed herein;

[0021] FIG.5 is a partially exploded view of co-packaged optics assemblies in accordance with embodiments disclosed herein;

[0022] FIG.6 is a partially exploded view of co-packaged optics assemblies in accordance with embodiments disclosed herein;

[0023] FIG.7 is a partially exploded view of co-packaged optics assemblies in accordance with embodiments disclosed herein;

[0024] FIG.8 is a partially exploded view of co-packaged optics assemblies in accordance with embodiments disclosed herein;

[0025] FIG.9 is a partially exploded view of co-packaged optics assemblies in accordance with embodiments disclosed herein;

[0026] FIG.10 is a partially exploded view of a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0027] FIG.11 schematically illustrates an assembly of the co-packaged optics assembly shown in FIG.10;

[0028] FIG.12 schematically illustrates cross-sections of a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0029] FIG.13 schematically illustrates a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0030] FIG.14 schematically illustrates a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0031] FIG.15 schematically illustrates an assembled view of a co-packaged optics assembly in accordance with embodiments disclosed herein;Attorney Docket No.: HI24-113PCT

[0032] FIG.16 schematically illustrates a partially exploded view of a connector assembly in accordance with embodiments disclosed herein;

[0033] FIG.17 schematically illustrates a partially exploded view of a connector assembly in accordance with embodiments disclosed herein; and

[0034] FIG.18 schematically illustrates a co-packaged optics assembly in accordance with embodiments disclosed herein;

[0035] 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

[0036] 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 present 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.

[0037] 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.

[0038] 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.Attorney Docket No.: HI24-113PCT

[0039] 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.

[0040] Cartesian coordinates are used in some of the Figures for reference and are not intended to be limiting as direction or orientation.

[0041] For purposes of description herein, to 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.

[0042] 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 to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation.

[0043] FIG.1 schematically illustrates a partially exploded view of one exemplary embodiment of a co-packaged optics assembly 100, including a PIC attachment assembly or receptor assembly 200 (left side) configured to couple or attach to the PIC. In this embodiment, the receptor assembly 200 is preferably configured for permanent attachment to the PIC. The receptor assembly 200 includes a prism P, which may be separated or integrated with a microlens array MLAr, and an alignment block 205, having one or more thru-holes 210a, 210b, and one or more waveguides W1, W2 disposed therein. The microlens array MLAr, the prism P, and the alignment block 205 are preferably manufactured from glass or a glass-based material. The co-packaged optics assembly 100 additionally includes a de-mateable connector assembly 300 (right side). The de connector assembly 300 includes a microlens array MLAc, a glass block or fiber array unit (alternatively an “FAU”)Attorney Docket No.: HI24-113PCT 305, having pins 310a, 310b, coupled to the microlens array MLAc. The FAU is configured to house an array of fibers (not shown).

[0044] When alignment of the receptor assembly 200 with the connector assembly 300 is primarily achieved using at least one pin or a plurality of pins, effective alignment may be difficult. In this exemplary embodiment of the connector assembly, two pins 310a, 310b are shown. Here, the angle of the connector assembly 300 with respect to the x-axis may not be fully defined or reliable, depending upon the assembly method. In addition, coupling of the receptor assembly 200 with the connector assembly 300 could be sensitive because of the potential offset of the pins 310a, 310b with respect to the contact surface (i.e. the surface that the PIC rests upon). If the connector assembly is particularly sensitive, angular misalignment (i.e. when the right side rotates up, e.g., by a force exerted on the FAU or fibers contained within the FAU) could result in a lateral offset. For example, if one of the pins is more dominant, deformation of the second pin could occur. Furthermore, the design of the connector assembly may not provide a means to ensure that polymer and / or glass surfaces included in the assembly are parallel. If the offsets are balanced between the two pins 310a, 310b, perpendicularity between the holes in the geometry of adjacent surfaces may be difficult to achieve with reliability.

[0045] When alignment between the PIC attachment assembly and 200 and the connector assembly is achieved by coupling with a polymer contact surface, the pins 310a, 310b are preferably configured for lateral alignment with thru-holes 210a, 210b, which are configured to receive the pins 310a, 310b. In this instance, some pin deformation can be expected. Moreover, the angle of the connector assembly 300 with respect to the x-axis may not be fully defined or reliable, and parallelism of various surfaces (e.g. glass-to-glass- and polymer- to-polymer-surfaces) could be difficult to achieve with reliability. Additional issues, using this type of alignment method include lack of consistency of polymer wall-thicknesses, deformation of the assemblies during / after reflow processes, and high stresses of the respective assemblies included in the co-packaged optics may be induced by an over- constrained design.

[0046] Referring to FIG.2, an embodiment of a co-packaged optics assembly 500 is configured to address potential issues of the embodiment of the co-packaged optics assembly 100. In this configuration, the co-packaged optics assembly 500 includes a receptor assembly 600, which is preferably permanently attached to a PIC, and a connector assemblyAttorney Docket No.: HI24-113PCT 700 configured for coupling with the receptor assembly 600. The receptor assembly 600 includes a prism P1, a proximate MLAr1, a distal MLAr2, and an alignment block / waveguide assembly 605, having a plurality of waveguides W1, W2 defined therein. Although two waveguides are shown, the number of waveguides shown and described herein should not be construed as limiting. The connector assembly 700 includes an FAU 705, having a plurality of fiber arrays disposed FA1, FA2. Each fiber array includes a plurality of fibers F1, F2. At least a portion of each of the plurality of fibers are contained respectively in a fiber optic cable C1, C2, which may branch into fiber harnesses FH1, FH2. Here, the fiber harnesses are shown as two y-shaped branches, however additional branches are contemplated. The fiber harnesses FH1, FH2 are coupled to a plurality of connectors 400.

[0047] Still referring to FIG.2, the PIC is configured to accept an array of expanded beams at an angle defined with respect to the uppermost PIC surface PS and the prism P1. The expanded beams EB1a, EB2a are arranged in an array of 2x40. However, the co-packaged optics assembly 500 may also be configured to provide other expanded beam-fiber array arrangement geometries. The co-packaged optics assemblies disclosed herein provide optical connection of the PIC to fiber arrays FA1 and FA2, each including a plurality of fibers F1, F2, via expanded beams EB1a, EB2b. In this embodiment of the co-packaged optics assembly 500, expanded beams EB1a, EB1b correspond to fiber array FA1 and expanded beams EB2a, EB2b correspond to fiber array FA2.

[0048] In some embodiments, the receptor assembly 600 includes at least one waveguide assembly 610, having pluralities of waveguides W1, W2 defined therein. The pluralities of waveguides preferably correspond to the geometry of the beam array, e.g. two layers of 40 waveguides each. The waveguides may be formed through an arrangement of fibers AF1, AF2, AF3 in fiber array units (FAUs) OFA1, OFA2, OFA3, shown by way of example in FIG.3. Specifically, FIG.3 illustrates front or rear view of a two-dimensional arrangement of optical fibers in an alignment block or FAU without (left) and with a spacer-layer (right).The arrangement of alignment blocks / FAUs OFA1, OFA2, OFA3 further includes a plurality of upper and lower v-grooves 602U, 602L formed in a glass substrates GS1U, GS1L, GS2U, GS2L, GS3U, GS3L. Arrangements of the FAUs may be offset (top left), aligned (lower left), or separated by a spacer S or a bonding agent (right). The v-groove configuration shown should not be construed as limiting, as other groove configurations are contemplated.Attorney Docket No.: HI24-113PCT

[0049] Referring to FIG.4, alternatively, a plurality of waveguides WA1U, WA1L, WA2U, WA2L may be formed through the arrangement of a plurality of fibers F in an optical fiber arrangement assembly OFA4, OFA5. The waveguides in this configuration are prepared ion-exchanged waveguides disposed respectively in glass substrates GS4, GS5. In another configuration, fiber array unit OFA6 includes pluralities of waveguides WA3, WA4. Each of the pluralities of waveguides WA3, WA4 includes an arrangement of fibers F (represented by the innermost circles shown in FIG.4). The pluralities of waveguides WA3, WA4 may be arranged with respect to two substrates GS6a, GS6B, which are coupled or bonded using a spacer S or bonding agent. The pluralities of waveguides WA3, WA4 includes one layer of waveguides each. In each of these configurations a series of eight (8) waveguides are shown. However, the number of waveguides shown should not be construed as limiting.

[0050] Referring back to FIG.2, the receptor assembly 600 preferably includes a plurality of microlens arrays (MLAs), e.g. MLAr1, MLAr2, disposed on or substantially adjacent to coupling surfaces. Such surfaces are configured to couple with the PIC and the connector assembly 700 by expanded optical beams. On the side to be coupled to the PIC, the receptor assembly 600 includes a prism P1, or optical turn, which provides the required angle of the expanded beam(s) (represented by the dark arrow-like elements EB1, EB2). In some configurations, at least some of the receptor assembly 600 is preferably enclosed by a housing structure (See, e.g. FIGs.5) that provides alignment and latching features for coupling, alignment, and / or connection of the receptor assembly 600 with the connector assembly 700. In some embodiments, the receptor assembly 600 is permanently attached to the PIC during an active alignment step to ensure the best possible optical coupling of the expanded beams EB1b, EB2b. The expanded beam optical link (represented by expanded beams, i.e. the darker arrow-like elements EB1b, EB2b) between the receptor assembly 600 and connector assembly 700 can have a substantially higher sensitivity to angular offset compared to a physical contact optical link (e.g., a MTP connector link). This embodiment of the co-packaged optics assembly shown in FIG.2, in particular, has substantially reduced sensitivity to lateral and axial offsets. The connector assembly 700 preferably includes an FAU or a substantially equivalent structure configured to arrange fibers into a pattern. A microlens array MLAc provides expanded beam connectivity to the receptor assembly 600 via MLAr2. In some co-packaged optics assemblies, the connector assembly 700 is enclosedAttorney Docket No.: HI24-113PCT in various types of housing structures configured that provide alignment and latching features to the receptor assembly.

[0051] FIG.5 illustrates another embodiment of a co-packaged optics assembly 800, in various states of assembly. In this configuration, the co-packaged optics assembly 800 includes a receptor assembly 900, a connector assembly 1000, and a housing structure 1100 (including a housing receptor section 1100R, and a housing connector section 1100C). The receptor assembly 900 is configured as an alignment block assembly 903 having a glass block 905 and a glass prism P2. The prism P2 may be coupled to or integral with the glass block 905. In this configuration, the prism P2 is integral to the alignment block / waveguide assembly 905. The connector assembly 1000 includes an FAU or an equivalent structure 1005 configured to arrange fibers (not shown) into a pattern. The connector assembly 1000 also preferably includes a microlens array MLAc1 (FIG.6), which is configured to provide expanded beam connectivity to the receptor assembly 900 via microlens array MLAr3. The connector assembly 900 is configured for enclosure in the housing structure 1100.

[0052] Still referring to FIG.5, the co-packaged optics assembly 800 thus includes the receptor assembly 900, having an alignment block / waveguide assembly 903 coupled to a PIC, the connector assembly 1000, and the housing structure 1100 (receptor side housing section 1100R, connector side housing section 1100C). The housing structure 1100 includes various elements for coupling, aligning, and or connecting the receptor assembly 900 with the connector assembly 1000. The connector assembly 1000 is shown disposed within an interior 1122 of the connector side housing section 1100C. The receptor assembly 900 is shown partially disposed within an interior 1120 of the receptor side housing section 1100R. On the connector assembly 1000, two pins 1010a, 1010b (FIG.6) are placed in v-grooves 1011a, 1011b of an FAU or equivalent structure 1005, which arranged adjacent to a fiber array (not shown) to define the angle and provide fine alignment with corresponding grooves or receiving areas 910a, 910b (e.g. v-grooves) of the receptor assembly 900. The pins 1010a, 1010b are configured to be positioned with holes 911a, 911b in the receptor assembly 900, as particularly shown in FIG.6.

[0053] Coarse alignment in the co-packaged optics assembly 800 is preferably provided by latches and / or a plurality of male-female snaps integrated into the housing structure 1100, as shown particularly in FIG.5. The latches 1112a, 1112b, 1116a, 1116b and the snaps 1114a, 1114b, 1118a, 1118b (bottom latch 1116a, and bottom snap 1118a are not shown in FIG.5,Attorney Docket No.: HI24-113PCT but are located on the bottom of the connector side housing section 1100C and mirror latch 1112a, and snap 1114a) are configured to couple with corresponding latch grooves 1113a, 1113b, 1117a, 1117b and snap grooves 1115a, 1115b, 1119a, 1119b (the latter two snap grooves are not shown in FIG.5, but are located on the bottom of the receptor side housing section 1100R and mirror snap grooves 1115a, 1115b) on the receptor assembly 900.

[0054] Additionally, the receptor section 1100R of housing structure 1100 further includes one or more alignment ridges 1122 configured to compensate when there is overtravel of the snaps / latches. The one or more alignment ridges 1122 not only provides alignment, but when positioned adjacent to the connector section 1100C of the housing structure 11000 a seal 1100S is formed, which substantially seals the optical path. This configuration of the co- packaged optics assembly 800 thus provides sealing of the optical path between the MLAs (e.g. the MLA assembly shown in FIGs.2 and 6) and protection from the surrounding environment. The distance between the MLAs (i.e. an axial offset) is therefore primarily substantially based upon the positioning and alignment of the overall housing structure 1100.

[0055] FIG.6 further illustrates the co-packaged optics assembly 800, excluding the housing structure 1100, to further illustrate the symmetrical arrangement of pins 1010a, 1010b with grooves 910a, 910b of the receptor assembly 900 such that a substantially stable connection is provided between the receptor assembly 900 and the connector assembly 1000. Moreover, the co-packaged optics assembly 800 is configured to be substantially less sensitive to force exerted on the fibers. Furthermore, integrating the pins 1010a, 1010b into the glass elements (e.g. the alignment block and the FAU) ensures substantial high-precision alignment and substantial temperature stability of the alignment.

[0056] FIGs.7, 8, and 9 illustrate additional concepts for co-packaged optics assemblies. Here, one or more pins are integrated with or connected to a housing structure and coupled to an FAU or an equivalent structure. In each embodiment, receptor side housing section has at least one hole on the top and a slotted arrangement on the bottom. The hole defines the x- and y-positions with respect to the co-packaged optics assemblies, while the one or more slots defines the rotation around the z-axis (fiber axis). Datum A (i.e. a surface of the housing structure on the receptor assembly side) defines the rotations around the x- and y-axes. While the snap elements are configured to limit the travel distance along the z-direction. In this instance a precise definition may not be required because of the expanded beam coupling.Attorney Docket No.: HI24-113PCT The bottom latches are realized in a sideways configuration to allow for reduced height (FIG. 9) of the overall co-packaged optics assembly.

[0057] Referring to FIGs.7 and 8, an embodiment of a co-packaged optics assembly 1200 includes a receptor assembly 1300, a connector assembly 1300, and a housing structure 1500, having a receptor side housing section 1500R and a connector side housing section 1500C. In this configuration, a pin / hole is provided on the top part of the housing and a pin / slot feature is included at the bottom of the housing. Datum A is configured to further define the angle and positioning of the receptor side housing section with respect to the x-axis. At least one pin 1540 is connected to or integral with the connector side housing section 1500C ensure fine alignment along the x- and y- axes. Upon assembly, an alignment ridge 1522 provides an enclosed cavity when snaps are engaged, resulting in a seal 1500S.

[0058] Referring particularly to FIG.8, the receptor assembly 1300 is configured as a glass block assembly 1303 having a glass block 1305 and a glass prism P3. In this configuration, the prism P3 is integral to the alignment block / waveguide assembly 1305. The receptor assembly 1300 also includes a microlens array MLAr4 adjacent to a proximate surface 1307 of the alignment block / waveguide assembly 1305. The connector assembly 1400 includes an FAU or an equivalent structure 1405 configured to arrange fibers (not shown) into a pattern. The connector assembly 1400 also preferably includes a microlens array MLAc3, having an array feature 1450, which is configured to provide expanded beam connectivity to the receptor assembly 1300 via microlens array MLAr4. The connector assembly 900 is configured for enclosure partially or fully within the housing structure 1500.

[0059] Referring to both FIGs.7 and 8, the co-packaged optics assembly 1200 thus includes the receptor assembly 1300, having an alignment block / waveguide assembly 1305 coupled to a PIC, the connector assembly 1400, and the housing structure 1500 (receptor side housing section 1500R, connector side housing section 1500C). Similar to some other embodiments, the housing structure 1500 includes various elements for coupling, aligning, and or connecting the receptor assembly 1300 with the connector assembly 1400. The connector assembly 1400 is this configured for positioning within an interior 1522 of the connector side housing section 1500C. The receptor assembly 1300is shown partially disposed within an interior 1520 of the receptor side housing section 1500R. On the connector side housing section 1500C, one or more pins 1510, disposed in holes 1530, 1532,Attorney Docket No.: HI24-113PCT are configured to be positioned with holes 1509, 1511 in the receptor side housing section 1500R.

[0060] Coarse alignment in the co-packaged optics assembly 1200 is preferably provided by latches, tabs, and / or a plurality of male-female snaps integrated into the housing structure 1500, as shown particularly in FIG.7. The latches 1512a, 1512b, tabs 1507a, 1507b (bottom tab not shown, but mirrors tab 1507a) and the snaps 1514a, 1514b are configured to couple with corresponding latch grooves 1513a, 1513b and snap grooves 1115a, 1115b on the receptor side housing section 1500R. Additionally, the receptor side housing section 1500R of housing structure 1500 further includes one or more alignment ridges 1522 configured to compensate when there is overtravel of the snaps / latches. The one or more alignment ridges 1522 not only provides alignment, but when positioned adjacent to the connector section 1500C of the housing structure 1500 a seal 1500S is formed, which substantially seals the optical path. This configuration of the co-packaged optics assembly 1200 thus provides sealing of the optical path between the MLAs (e.g. as shown in FIGs.8) and protection from the surrounding environment, i.e. environmental contaminants.

[0061] FIG.8further illustrates the co-packaged optics assembly 1200, excluding the housing structure 1100, to further illustrate how the microlens arrays MLAr4 and MLAc3 would be positioned. This configuration of the co-packaged optics assembly 1200 is also substantially less sensitive to forces which could be exerted on the fibers contained in the alignment block and the FAU. This configuration also ensures substantial alignment of the respective elements contained within the co-packaged optics assembly.

[0062] Referring to FIG.9, another embodiment of a co-packaged optics assembly 1600 is shown, including a receptor assembly 1700, a connector assembly 1800, and a housing structure 1900, having a receptor side housing section 1900R and a connector side housing section 1900C. The receptor assembly 1700 is shown fully contained within the receptor side housing section 1900R, while the connector assembly 1800 is shown partially contained within the connector side housing section 1900C. A lid L is also shown in this configuration.

[0063] In this configuration, the housing structure 1900 includes a receptor side housing body 1901R, having an interior cavity 1902R and a connector side housing body 1901C, having an interior cavity 1902C. The receptor side housing body 1901R is defined by a top wall 1903, a bottom wall 1904, and sidewalls 1921a, 1921b. Extending from the top wallAttorney Docket No.: HI24-113PCT 1903 are an upper pin 1940U and two overhang latches 1912a, 1912b. The two overhang latches 1912a, 1912b include inward facing latch portions 1923a, 1923b. The two overhand latches 1912a, 1912b preferably form l-shapes. Extending from the bottom wall 1904 are a bottom pin 1940L, and bottom latches 1912a, 1912b, having upwardly extending snaps 1918a, 1918b. The connector side housing body 1901C includes an upper surface 1960, having a t-shaped mating element 1962 configured for positioning between the two overhang latches 1912a, 1912b.

[0064] In an additional concept disclosed herein, fine alignment can be achieved by features contained on the surface(s) of MLAs. These features may be configured to provide high-precision alignment since features in glass can be fabricated very accurately. For example, by recessing the MLA lenses a frame around the optical path is created, in which features for the alignment in vertical and / or horizontal direction may be fabricated, e.g., by etching (FIG.10). The interlocking features may have slanted or rounded edges for easier engagement (FIG.11). Alternatively, a double frame may be created around the optical path, which also provides an additional sealing functionality (FIG.12). Rough alignment may again be provided by snaps or hooks in the housing structure. FIGs.13, 14, and 15 further illustrate details of the concepts shown in FIGs.10-11.

[0065] Referring to FIGs.10, 11 and 12, a co-packaged optics assembly 2000 is shown, including a receptor assembly 2100 and a connector assembly 2200 for coupling with the receptor assembly 2100. The receptor assembly 2100 includes prism P4, an alignment block / waveguide assembly 2105, and a microlens array MLAr5. The microlens array MLAr5 includes a recess feature 2170, having an interior lens 2171 with an array feature 2172, upper and lower cutouts 2173, 2174, and side cutouts 2175a, 2175b. The connector assembly 2200 includes a microlens array MLAc5, a glass block or fiber array unit (alternatively an “FAU”) 2205. The microlens array MLAc5 includes a mating feature 2180, having an interior lens 2181 with an array feature 2182, upper and lower extensions 2183, 2184, and side extensions 2185a, 2185b. FIGs.13 and 14 shows the co-packaged optics assembly 2000 in mated and unmated positions, coupled with the housing structure 1100.

[0066] FIG.15 is another version of a co-packaged optics assembly 2400, having a similar structure shown in FIGs.10 and 11, but excluding interior lenses. FIG.16 illustrates the co- packaged optics assembly shown in FIG.9 flipped with spring elements 2490a, 2490b disposed in snap grooves.Attorney Docket No.: HI24-113PCT

[0067] FIGs.16, 17, 18, and 19 show variants of the housing connecting receptor assemblies and connector assemblies. FIG.16 shows a housing with snap receptacles fitted with springs. FIG.17 shows an alternate version of the housing structure 2500, with the connector side housing section 2500C, having the latches 2512a, 2512b, and snaps 2514a, 2514b flipped. The receptor side housing section 2500R includes corresponding grooves 2517a, 2517b.

[0068] FIG.18 shows an alternate receptor side housing section 2600R, having dove- shaped grooves 2666U, 2666L. Other keying elements are also possible. FIG.19 shows a housing with a spring feature intended to center connector and receptor with respect to each other and compensate any height differences of the glass and / or housing elements.

[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.: HI24-113PCT Claims What is claimed is:

1. A co-packaged optics assembly, comprising: a receptor assembly, comprising an alignment block assembly; a connector assembly, comprises at least one fiber array unit (FAU) configured to arrange a plurality of fibers, wherein upon assembly, the receptor assembly and the connector assembly are coupled such that the co-packaged optics assembly includes a high-density interface such that the connector assembly is configured to provide expanded beam connectivity to the receptor assembly.

2. The co-packaged optics assembly of claim 1, wherein the receptor assembly comprises at least one microlens array.

3. The co-packaged optics assembly of claim 2, wherein the at least one microlens array is configured to generate an expanded optical beam.

4. The co-packaged optics assembly of claim 3, further comprising an optical turn configured to interface with the expanded optical beam.

5. The co-packaged optics assembly of any one of claims 1-4, wherein the receptor assembly is permanently attached to a photonic integrated circuit (PIC).

6. The co-packaged optics assembly of claim 5, wherein the receptor assembly further comprises a housing structure providing alignment features and latching features.

7. The co-packaged optics assembly of any one of claims 1-6, wherein the connector assembly includes a plurality of grooves disposed in the FAU.

8. The co-packaged optics assembly of claim 7, wherein the plurality of grooves comprises at least one v-groove for fiber alignment.Attorney Docket No.: HI24-113PCT 9. The co-packaged optics assembly of any one of claims 6-8, wherein the housing structure includes at least one latch configured for coupling with at least one latch groove for coarse alignment.

10. The co-packaged optics assembly of any one of claims 1-9, wherein the receptor assembly includes a prism configured to provide an optical turn.

11. The co-packaged optics assembly of claim 10, wherein the prism is integral to an alignment block of the receptor assembly.

12. The co-packaged optics assembly of claim 11, wherein the alignment block further comprises waveguides formed therein.

13. The co-packaged optics assembly of claim 12, wherein the waveguides are ion-exchanged waveguides.

14. The co-packaged optics assembly of claim 12 or 13, wherein the waveguides are defined by optical fibers disposed in an array.

15. The co-packaged optics assembly of any one of claims 1-14, wherein optical is achieved at least in part through optical features formed on surfaces of microlens arrays.

16. The co-packaged optics assembly of claim 15, wherein the alignment features comprise recesses configured to interlock for alignment.

17. The co-packaged optics assembly of claim 16, wherein the recesses are configured to provide additional sealing of the optical path.

18. The co-packaged optics assembly of any one of claims 1-17, wherein the de-matable connector assembly further includes pins integrated into glass elements.

19. The co-packaged optics assembly of claim 18, wherein the pins are disposed symmetrically with respect to an axis to provide substantially stable alignment.

20. The co-packaged optics assembly of any one of claims 1-19, wherein the optical path between the receptor assembly and the connector assembly is substantially sealed against environmental contaminants.

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