Connecting optical connector with co-packaged optical device

Aspects described herein include an apparatus supporting optical alignment with one or more optical waveguides optically exposed along an edge of a photonic integrated circuit (IC). The apparatus comprises a frame body comprising an upper portion defining a reference surface, and a lateral portion defining an interface for an optical connector connected with one or more optical fibers. The lateral portion comprises one or more optical components defining an optical path through the lateral portion. The one or more optical components are arranged relative to the reference surface such that the one or more optical components align with (i) the one or more optical waveguides along at least one dimension when the reference surface contacts a top surface of an anchor IC, and with (ii) the one or more optical fibers when the optical connector is connected at the interface.

TECHNICAL FIELD

Embodiments presented in this disclosure generally relate to optical engines (OE) for co-packaged optical (CPO) applications, and more specifically, to a frame device used to connect an optical connector with an OE device.

BACKGROUND

Fabrication of co-packaged optical (CPO) devices may be challenging as it typically requires an integration of diverse components and processes. For example, co-packaged optical devices may include one or more electronic integrated circuits (EICs) and one or more photonic integrated circuits (PIC), which may include digital signal processors, silicon photonics, and/or external optical connections (such as fiber array units arranging a plurality of optical fibers). Some examples of fabrication processes include package assembly, optical fiber attachment, and/or printed circuit board and socket assembly.

In optical transceivers, a fiber array unit (FAU) may be actively aligned and attached to a photonic integrated circuit using edge coupling or surface coupling. An optical connector is attached to a housing of the optical transceiver, and is optically connected with the FAU using short optical fibers (pigtails). In these implementations, the number of optical fibers may be limited by the FAU, and a mating force to the optical connector is typically absorbed by the housing and/or the cage on a front panel of the transceiver.

For CPO devices, however, there is typically no housing or cage to absorb the mating force to the optical connector. In addition, due to thermal, mechanical, and/or spatial constraints of the co-packaging, it may be preferable to integrate the FAU into a connector to eliminate the need for pigtails, which may reduce the number of optical connections in a link and thus an overall optical link loss.

In addition, CPO devices that are compatible with surface mount technology (SMT) reflow soldering may offer broad applicability to optical communications, high-performance computing, neural networks, high performance graphics, and automotive applications, and so forth.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Overview

One embodiment presented in this disclosure is an apparatus supporting optical alignment with one or more optical waveguides optically exposed along an edge of a photonic integrated circuit (IC). The apparatus comprises a frame body comprising an upper portion defining a reference surface, and a lateral portion defining an interface for an optical connector connected with one or more optical fibers. The lateral portion comprises one or more optical components defining an optical path through the lateral portion. The one or more optical components are arranged relative to the reference surface such that the one or more optical components align with (i) the one or more optical waveguides along at least one dimension when the reference surface contacts a top surface of an anchor IC, and with (ii) the one or more optical fibers when the optical connector is connected at the interface.

One embodiment presented in this disclosure is a method of fabricating an optical apparatus. The method comprises optically aligning one or more optical components of a lateral interface of a frame body with one or more optical waveguides of a photonic integrated circuit (IC). The one or more optical waveguides are optically exposed along one or more lateral edges of the photonic IC. The frame body further comprises an upper portion defining a reference surface. Optically aligning the one or more optical components comprises contacting the reference surface with a top surface of an integrated circuit (IC). The method further comprises adhering the frame body to the IC, wherein adhering the frame body comprises applying an adhesive through one or more openings defined through the upper portion and extending to the top surface. The method further comprises connecting an optical connector to the frame body. One or more optical fibers are connected to the optical connector. Connecting the optical connector optically aligns the one or more optical fibers with the one or more optical waveguides through the lateral interface.

One embodiment presented in this disclosure is an optical apparatus comprising an anchor integrated circuit (IC), a photonic IC comprising one or more optical waveguides optically exposed along an edge of the photonic IC, and a frame. The frame comprises a lateral interface configured to receive an optical connector. One or more optical fibers attached to the optical connector are optically aligned with the one or more optical waveguides through the lateral interface. The frame further comprises an attachment interface configured to distribute a mating force of the optical connector across a top surface of the anchor IC.

EXAMPLE EMBODIMENTS

Embodiments of this disclosure are generally directed to an apparatus that supports optical alignment with one or more optical waveguides that are optically exposed along an edge of a PIC. The apparatus comprises a frame body comprising an upper portion defining a reference surface, and a lateral portion defining an interface for an optical connector connected with one or more optical fibers. The lateral portion comprises one or more optical components defining an optical path through the lateral portion. The one or more optical components are arranged relative to the reference surface such that the one or more optical components align with (i) the one or more optical waveguides along at least one dimension when the reference surface contacts a top surface of an anchor IC, and with (ii) the one or more optical fibers when the optical connector is connected at the interface.

In some embodiments, the frame body operates to anchor the optical connector to the anchor IC (which may be the photonic IC or another IC), to distribute the mating force of the optical connector across the top surface of the anchor IC, and/or to expose surface area of the anchor IC. Beneficially, connecting the optical connector with the frame body avoids challenges associated with directly connecting the optical connector to the photonic IC, such as excessive mating forces that can damage an end face of the photonic IC. For example, optical connectors that rely on physical fiber contact tend to accumulate excessive forces, e.g. about 2.5 N per fiber, that are absorbed by the photonic IC. Optical connectors that do not rely on physical contact (e.g., air gap, expanded beam) may still exert about 2.3 N in a mated state, although this amount may be independent of a fiber count.

Using the frame body may also increase an amount of surface area available for attaching additional component(s) to the anchor IC. Using the frame body may also be compatible with active alignment and/or precision vision-assisted alignment processes. Using the frame body may also support using different types of adhesives, which may be compatible with SMT reflow soldering processes.

FIG.1is a cross-sectional view of an optical engine (OE) system100. The OE system100may provide any suitable functionality, such as an optical transceiver. The OE system100sits on a printed circuit board (PCB)105, and comprises of a substrate110conductively connected to the PCB105, a lower IC115-1conductively connected to the substrate110, and upper ICs115-2,115-3conductively connected to the lower IC115-1. In some embodiments, the substrate110, the lower IC115-1, and the upper ICs115-2,115-3may be assembled into a subassembly (e.g., a standalone OE device) that is then mounted to the PCB105. The conductive connections between the PCB105, the substrate110, the lower IC115-1, and/or the upper ICs115-2,115-3may be implemented in any suitable form, such as a ball grid array (BGA).

The lower IC115-1and the upper ICs115-2,115-3may have any suitable functionality. In some embodiments, the lower IC115-1is a photonic IC comprising one or more optical waveguides120-1defined therein, and the upper IC115-2is an electronic IC. In some embodiments, the lower IC115-1is an electronic IC and the upper IC115-2is a photonic IC comprising one or more optical waveguides120-2defined therein. In some embodiments, the upper IC115-3is a dummy IC.

The one or more optical waveguides120-1,120-2may be formed of any semiconductor material(s) suitable for propagating light, such as monocrystalline silicon, silicon nitride, polysilicon, and so forth. In some embodiments, the one or more optical waveguides120-1,120-2are formed in a layer of a silicon-on-insulator (SOI)-based device. For example, the one or more optical waveguides120-1,120-2may be formed in an active (silicon) layer of an SOI wafer, a silicon nitride layer deposited above the active layer, and so forth.

The one or more optical waveguides120,1,120-2are optically exposed along one or more edges of the respective photonic IC. In some embodiments, the one or more edges comprise lateral edge(s) of the photonic IC. In some embodiments, the one or more edges comprise a top surface of the photonic IC. As used herein, “optically exposed” indicates that the one or more optical waveguides120-1,120-2can optically couple with an external light-carrying medium, such as with an optical fiber155attached to an optical connector150. “Optically exposed” encompasses implementations where the one or more optical waveguides120-1,120-2are physically exposed at the one or more edges, or are slightly recessed from the one or more edges (e.g., 1-5 microns) but can nonetheless optically couple with the external light-carrying medium. “Optically exposed” also encompasses implementations having one or more intermediate optical components between the one or more optical waveguides120-1,120-2and the external light-carrying medium, such as edge couplers and grating couplers. The intermediate optical component(s) may be physically exposed at the one or more edges, or slightly recessed from the one or more edges. In some embodiments, the intermediate optical component(s) comprise a multi-prong waveguide adapter as described in U.S. Pat. No. 9,274,275, entitled “Photonic integration platform”, which is herein incorporated by reference.

The OE system100comprises a frame125that adheres to the upper IC115-2and/or the upper IC115-3. In this way, the upper IC115-2and/or the upper IC115-3may operate as an anchor IC. The frame125comprises an upper portion130defining a reference surface165, and a lateral portion135defining an interface140(also referred to as a lateral interface) for an optical connector150. The frame125may be formed of any suitable material(s). In some embodiments, the upper portion130and the lateral portion135are integrally formed of a same material. For example, the frame125may be formed of optical resin. In other embodiments, the upper portion130and the lateral portion135are separately formed of the same material or different materials, and are joined together.

The optical connector150may be of any suitable type, whether standardized or proprietary. In some embodiments, the optical connector150attaches to one or more optical fibers155, and arranges the corresponding optical core(s)160with a predefined arrangement. In some embodiments, the optical connector150comprises a FAU that arranges a plurality of optical fibers155.

The frame125is dimensioned to arrange the optical connector150with a predetermined alignment at the interface140. In some embodiments, the interface140of the lateral portion135and/or other portions of the frame125comprises alignment feature(s) that urge the optical connector150toward the predetermined alignment. In some embodiments, the frame125further comprises mechanical feature(s) that retain one or more latching features of the optical connector150. In one example, the upper portion130comprises grooves that receive corresponding tabs of the optical connector.

The interface140of the lateral portion135includes one or more optical components145that align with the optical core(s)160when the optical connector150is connected to the frame125. The one or more optical components145define an optical path through the lateral portion135, and are arranged relative to the reference surface165such that the one or more optical components145align with (i) the one or more optical waveguides120-1,120-2along at least one dimension when the reference surface165contacts the top surface170-2,170-3of the anchor IC, and with (ii) the one or more optical fibers155when the optical connector150is connected at the interface140. In some embodiments, the one or more optical components145comprise an array of collimator lenses. In some embodiments, the one or more optical components145comprise one or more mirrors. Some exemplary arrangements of the one or more optical components145are discussed in greater detail below with respect toFIGS.3A-3D.

When the reference surface165contacts a top surface170-2of the upper IC115-2and/or a top surface170-3of the upper IC115-3, the optical waveguide(s)120-1,120-2are optically aligned with the one or more optical components145of the interface140along at least one dimension. In some embodiments, the frame125comprises one or more alignment features that contact the photonic IC, or the other IC, to passively align one or more optical components145of the lateral interface140with the one or more optical waveguides120-1,120-2along at least one dimension. Some exemplary arrangements of the alignment features of the frame125are discussed in greater detail below with respect toFIGS.4A and4B.

FIG.2is a perspective view of a frame200for connecting an optical connector with a co-packaged optical device. The features depicted inFIG.2may be used in conjunction with other embodiments. For example, the frame200represents one possible implementation of the frame125ofFIG.1.

The frame200comprises a frame body205in which the upper portion130and the lateral portion135are integrally formed. The frame body205defines an outer frame210connected with an inner frame215. The outer frame210has a substantially solid structure (although openings may be formed therethrough), while the inner frame215has a frame structure.

The upper portion130defines a plurality of openings220-1, . . . ,220-6,225,230extending therethrough. The opening225is centrally defined by the inner frame215, and the openings220-1, . . . ,220-4are defined between portions of the inner frame215and the outer frame210. As shown, the opening225is substantially circumscribed by the openings220-1, . . . ,220-4. The opening230is arranged laterally outward of the opening220-4. The openings220-5,220-6are arranged near the opening220-2and extend through the outer frame210.

The top surface of the upper IC (a photonic IC or another IC) is exposed through the openings220-1, . . . ,220-4,225. In some embodiments, the openings220-1, . . . ,220-4are adhesive openings into which adhesive is applied and cured to secure the frame body205to the top surface of the upper IC. The outer frame210, the inner frame215, and the openings220-1, . . . ,220-4thus define an attachment interface that distributes a mating force of an optical connector across the top surface of the upper IC.

The opening225may be dimensioned to allow additional component(s) to be attached to the top surface of the upper IC. In some embodiments, the opening225is a thermal interface opening into which a heat sink or other thermal interface may be inserted and attached to the upper IC at the top surface.

The opening230is an adhesive opening through which an index-matching adhesive may be deposited into an optical path between the optical waveguide(s) of the photonic IC and the optical component(s)145of the interface140. In some embodiments, the top surface of the upper IC and/or a top surface of a lower IC are exposed through the opening. Thus, the index-matching adhesive may attach the frame body205to the upper IC and/or the lower IC.

In some embodiments, the index-matching adhesive may be applied through the opening230(and cured) after passive and/or active alignment processes for optically aligning the optical component(s)145and the optical waveguide(s) of the photonic IC. In this way, the frame body205may be secured to the photonic IC in the optically-aligned arrangement. In some embodiments, the index-matching adhesive may also be applied through the openings220-5,220-6to secure the frame body205to the photonic IC (and/or other ICs) at additional locations.

In some embodiments, a first, index-matching adhesive is applied through the openings230,220-5,220-6and UV-cured to provide a temporary attachment (e.g., a tack) of the frame body205to the photonic IC and/or other ICs. A second adhesive may be applied through the openings220-1, . . . ,220-4and heat cured to provide a permanent attachment of the frame body205to the photonic IC (and/or other ICs). Subsequent heating processes, such as the heat curing of the second adhesive and/or SMT reflow solder processes, may cause the first adhesive to lose some or all of its mechanical rigidity. In this way, the heat curing causes the first adhesive to yield the mechanical attachment function while causing the second adhesive to assume the mechanical attachment function. Thus, a larger number of adhesives may be suitable for use as the first index-matching adhesive (e.g., silicones, epoxies), as mechanical rigidity is only temporarily needed.

The frame body205is dimensioned to arrange an optical connector (e.g., the optical connector150ofFIG.1) with a predetermined alignment at the interface140. When in the predetermined alignment, the one or more optical components145align with optical fiber(s) attached to the optical connector.

In some embodiments, the interface140comprises alignment feature(s) that urge the optical connector150toward the predetermined alignment. As shown, the frame body205comprises guides240arranged around the interface140, and surface features245extending from the plane of the interface140. The guides240couple with peripheral surfaces of the optical connector, and the surface features245couple with corresponding features at the face of the optical connector. As shown, the guides240include chamfered edges, and the surface features245comprise trapezoidal features that are received by corresponding recessed features of the optical connector. However, other implementations may include different shapes (e.g., cones, funnels) and/or different orientations (e.g., the surface features245may be recessed into the lateral portion135).

The frame body205comprises grooves235-1,235-2defined on opposing sides of the outer frame210. The grooves235-1,235-2receive and retain one or more latching features that project from the optical connector, such as corresponding tabs. Other implementations may include other types of mechanical features, which may include features projecting from the frame body205that are received by corresponding portions of the optical connector.

FIGS.3A-3Dillustrate different arrangements of optical components at a lateral interface140of a frame. The features depicted inFIGS.3A-3Dmay be used in conjunction with other embodiments.

In diagram300, the upper portion130contacts the upper IC115-2and the one or more optical components at the interface140are optically aligned with the one or more optical waveguides of the photonic IC (here, the lower IC115-1). As shown, a collimating lens310is optically aligned with the optical waveguide120-1through an edge coupler320in the photonic IC. In some embodiments, the edge coupler320comprises a multi-prong waveguide adapter (as described above; also referred to as a “multi-prong edge coupler”). Thus, when the optical waveguide120-1is operated by the photonic IC as a receiver channel, light305exiting the optical fiber155is propagated through the collimating lens310, and collimated light315is received by the edge coupler320. When the optical waveguide120-1is operated by the photonic IC as a transmitter channel, light315exits the edge coupler320and is propagated through the collimating lens310. The collimated light305is received by the optical fiber155.

In diagram325, while operating in a receiver configuration, a first mirror330redirects the light315from the collimating lens310, and a second mirror335redirects the once-redirected light into the edge coupler320. The process is generally reversed while operating in a transmitter configuration. In some embodiments, the first mirror330and the second mirror335each perform an orthogonal redirection of the light. In this way, the first mirror330and the second mirror335operate as a periscope that accommodates implementations having the optical waveguide120-1and the optical fiber at different heights. The first mirror330and/or the second mirror335may have any suitable shape, such as flat mirrors or parabolic mirrors. In some embodiments, the collimating lens310may be replaced by a parabolic mirror to provide a longer collimated beam.

In diagram340, the interface140and the collimating lens310are angled (i.e., a non-perpendicular orientation relative to a length of the optical waveguide120-1). Describing a receiver configuration, a mirror345redirects the light315from the collimating lens310. The process is generally reversed while operating in a transmitter configuration. The mirror345may have any suitable shape, such as a flat mirror or a parabolic mirror. In some embodiments, the collimating lens310may be replaced by a parabolic mirror to provide a longer collimated beam.

In diagram350, while operating in a receiver configuration, a mirror355redirects the light315from the collimating lens310into a grating coupler360disposed at or near a top surface of the photonic IC. The process is generally reversed while operating in a transmitter configuration. The mirror355may have any suitable shape, such as a flat mirror or a parabolic mirror. In some embodiments, the collimating lens310may be replaced by a parabolic mirror to provide a longer collimated beam.

FIGS.4A and4Billustrate different arrangements of alignment features of the frame125. The features depicted inFIGS.4A and4Bmay be used in conjunction with other embodiments. For example, contacting the alignment features of the frame125may align the one or more optical components145of the lateral interface with optical waveguides120-1of a photonic IC along at least one dimension.

The diagram400provides a top view of one implementation of the frame125. In the diagram400, the photonic IC (e.g., the upper IC115-2) comprises a plurality of ridges405-1,405-2,405-3,405-4that are spaced apart from each other. As shown, the ridges405-1,405-2are separated by a groove410-1, the ridges405-2,405-3are separated by a groove410-2, and the ridges405-3,405-4are separated by a groove410-3. In some embodiments, the depth of the grooves410-1,410-2,410-3extends fully through the photonic IC, such that a surface beneath the photonic IC is exposed. In other embodiments, the depth of the grooves410-1,410-2,410-3extends partly through the photonic IC. In some embodiments, beam collimation may be achieved by replacing the first mirror330or the second mirror335with a parabolic surface, as an alternate to beam collimation using the lens310.

As shown, an optical waveguide120-1is arranged in the ridge405-1, an optical waveguide120-2is arranged in the ridge405-2, and an optical waveguide120-3is arranged in the ridge405-3.

The frame125defines one or more alignment features that contact the photonic IC to passively align the optical components145with the optical waveguides120-1,120-2,120-3along at least one dimension. As shown, the optical components145comprise collimating lenses310-1,310-2,310-3, although other arrangements of the optical components145are also contemplated (e.g., as depicted inFIGS.3A-3D).

The frame125comprises a plurality of fingers415-1,415-2,415-3used to passively align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along the x-dimension. The plurality of fingers415-1,415-2,415-3are received into respective ones of the grooves410-1,410-2,410-3. In some embodiments, each of the fingers415-1,415-2,415-3include lateral stand-offs420that contact lateral edges of the respective ridges405-1,405-2,405-3. As shown, each of the fingers415-1,415-2,415-3include two (2) lateral stand-offs420, although other numbers of lateral stand-offs are also contemplated. In other embodiments, the lateral stand-offs420may be omitted and lateral edges of the fingers415-1,415-2,415-3contact the lateral edges of the respective ridges405-1,405-2,405-3.

The frame125further comprises depth stand-offs425that contact endface portions of the photonic IC. As shown, one of the depth stand-offs425contacts an endface of the ridge405-1at a location laterally outward of the optical waveguide120-1, and the other of the depth stand-offs425contacts an endface of the ridge405-4(which does not include an optical waveguide). Although the frame125includes two (2) depth stand-offs425, other numbers of depth stand-offs are also contemplated. In other embodiments, the depth stand-offs425may be omitted and edges of the frame125contact the endface portions of the photonic IC. In this way, the frame125may also passively align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along the z-dimension.

The diagram430provides a cross-section view of another implementation of the frame125. In the diagram400, the frame125comprises the depth stand-offs425to align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along the z-dimension. The frame125further comprises height stand-offs435that contact a top surface of the ridge405-3.

Although the frame125includes two (2) height stand-offs435, other numbers of height stand-offs are also contemplated. In other embodiments, the height stand-offs435may be omitted and a surface of the frame125contacts the top surface of the ridge405-3or other portions of the photonic IC. In this way, the frame125may also passively align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along the y-dimension.

AlthoughFIGS.4A and4Beach depict implementations of the frame125that passively align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along two dimensions, alternate implementations of the frame125may include alignment features that passively align along a different number of dimensions (e.g., one or three). Further, in some embodiments, active alignment may be performed in conjunction with the passive alignment to align the collimating lenses310-1,310-2,310-3with the optical waveguides120-1,120-2,120-3along one or more additional dimensions.

FIGS.5A and5Billustrate unmated and mated configurations of the optical connector150with the frame125, according to one or more embodiments. The features illustrated in diagrams500,545may be used in conjunction with other embodiments.

Diagram500is a top view of an unmated configuration of the optical connector150with the frame125. An areal extent510of the upper portion of the frame125is greater than an areal extent505of the top surface of the upper IC115-2. In this way, the frame125when adhered to the upper IC115-2is capable of distributing the mating force of the optical connector150across the top surface of the photonic IC (or other IC).

The optical connector150comprises a housing515into which a plurality of optical fibers520are inserted. The optical fibers520are attached to, and arranged by, a FAU525arranged within the housing515. A latch member530is attached to the FAU525within the housing515. The latch member530includes one or more latching features that mate with one or mechanical features of the frame125to retain the optical connector150. As shown, the latch member530includes two (2) arms535-1,535-2at opposing ends of the latch member530. The arms535-1,535-2include tabs540-1,540-2that project inward and that are dimensioned to be received and retained by the grooves235-1,235-2of the frame125, which is shown in the mated configuration in the diagram545.

In the mated configuration, the guides240are coupled with peripheral surfaces of the optical connector150(here, the FAU525). In some cases, in the mated configuration one or more surface features on the lateral portion of the frame125are coupled with corresponding features at the face of the optical connector150(the FAU525).

FIG.6is a method600of fabricating an optical apparatus, according to one or more embodiments. The method600may be used in conjunction with other embodiments, e.g., to fabricate the OE system100ofFIG.1.

The method600begins at block605, where one or more optical components of a lateral interface of a frame body are optically aligned with one or more optical waveguides of a photonic IC. In some embodiments, the photonic IC is attached with one or more additional ICs, such as an electronic IC and/or a dummy IC. In some embodiments, the photonic IC is part of a preassembled OE package, which in some cases may be mounted to a PCB.

Optically aligning the optical component(s) with the optical waveguide(s) may include passive alignment and/or active alignment processes. In some embodiments, optically aligning the optical component(s) with the optical waveguide(s) comprises (at block615) contacting a reference surface of an upper portion of the frame body with a top surface of an IC. In some embodiments, the IC is the photonic IC. In other embodiments, the IC is another IC (such as an electronic IC or a dummy IC) that is attached with the photonic IC. In some embodiments, optically aligning the optical component(s) with the optical waveguide(s) comprises (at block625) contacting one or more alignment features of the frame body with the photonic IC or the other IC.

At block635, the frame body is adhered to the IC. In some embodiments, adhering the frame body to the IC comprises (at block645) applying an index-matching adhesive through one or more first openings defined through the upper portion of the frame body. In some embodiments, the index-matching adhesive is deposited into an optical path between the one or more optical waveguides of the photonic IC and the one or more optical components of the frame body. In some embodiments, the index-matching adhesive is UV-cured to provide a temporary attachment (e.g., a tack) of the frame body to the IC.

In some embodiments, adhering the frame body to the IC comprises (at block655) applying a second adhesive through one or more openings defined through the upper portion of the frame body and extending to the top surface of the IC. In some embodiments, the second adhesive is heat cured to provide a permanent attachment of the frame body to the IC. The heat curing of the second adhesive may cause the index-matching adhesive to lose some or all of its mechanical rigidity. In this way, the heat curing causes the first adhesive to yield the mechanical attachment function while causing the second adhesive to assume the mechanical attachment function.

At block665, an optical connector is connected to the frame body. In some embodiments, connecting the optical connector comprises (at block675) optically aligning one or more optical fibers (attached to the optical connector) with the one or more optical waveguides through the lateral interface. In some embodiments, guides and/or surface features may be used to align the one or more optical fibers. In some embodiments, one or more latching features of the optical connector are retained by one or more mechanical features of the frame body. The method600ends following completion of block675.

FIGS.7A-7Cillustrate a sequence of fabricating an optical apparatus, according to one or more embodiments. The features illustrated in diagrams700,720,735may be used in conjunction with other embodiments, e.g., to perform some or all of the method600ofFIG.6.

In diagram700, a tool attaches to the frame125and moves the frame125toward the upper IC115-2. In some embodiments, a tool705attaches to the upper portion130of the frame125. In other embodiments, a tool710attaches to the lateral portion135of the frame125.

Each of the tools705,710may be further configured to align the frame125along one or more dimensions. In some embodiments, the tool705comprises a force sensor to detect a threshold resistance force (e.g., contacting alignment features) for performing passive alignment of the optical component(s)145of the frame125with optical waveguide(s) of the upper IC115-2or the lower IC115-1. In some embodiments, the tool710is attached to one or more optical fibers715-1,715-2for performing active alignment of the optical component(s)145of the frame125with optical waveguide(s) of the upper IC115-2or the lower IC115-1.

In diagram720, the tool705moves the frame125to contact the top surface of the upper IC115-2. When the optical component(s)145are optically aligned with the optical waveguide(s), an index-matching adhesive725is applied through the opening230, and an index-matching adhesive730is applied through the openings220-5,220-6. In some embodiments, the index-matching adhesive725,730is UV-cured to temporarily attach the frame125to the upper IC115-2and/or the lower IC115-1.

In diagram735, a second adhesive740is applied through the openings220-1, . . . ,220-4. In some embodiments, the second adhesive740is heat cured to permanently attach the frame125to the upper IC115-2and/or the lower IC115-1. The optical component(s)145remain optically aligned with the optical waveguide(s) through the index-matching adhesive725, despite any loss of mechanical rigidity of the index-matching adhesive725caused by the heat curing.