Integration of power and optics through cold plate for delivery to electronic and photonic integrated circuits

In one embodiment, an apparatus includes a cold plate comprising a first side and a second side, a photonic integrated circuit connected to a substrate positioned on the second side of the cold plate, and an optical path extending through the cold plate and optically coupled to the photonic integrated circuit for transmitting an optical signal between the photonic integrated circuit and the first side of the cold plate.

TECHNICAL FIELD

The present disclosure relates generally to power and optics integration, and more particularly, to power and optical signal distribution in an electronics and photonics package.

BACKGROUND

As ASIC (Application-Specific Integrated Circuit) process nodes advance and device power continues to increase, delivering requisite power is becoming more challenging. Higher power distribution also presents additional thermal challenges. When the ASIC or other electronic integrated circuit is packaged with a cold plate, additional difficulties arise in delivering power to the electronic integrated circuit and optical signals to a photonic integrated circuit.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Overview

In one embodiment, an apparatus generally comprises a cold plate comprising a first side and a second side, a photonic integrated circuit connected to a substrate positioned on the second side of the cold plate, and an optical path extending through the cold plate and optically coupled to the photonic integrated circuit for transmitting an optical signal between the photonic integrated circuit and the first side of the cold plate.

In one or more embodiments, the optical path comprises a waveguide for transmitting light through the cold plate and optics for directing light to or from the photonic integrated circuit. The apparatus may further comprise additional optics for directing light from the waveguide to a connector positioned on the first side of the cold plate. One or more of the waveguide and the optics may be defined by laser patterning.

In one or more embodiments, the optical path comprises an optical structure actively aligned to the photonic integrated circuit. In one or more embodiments, the optical path is passively aligned to the photonic integrated circuit.

In one or more embodiments, the optical path comprises an optical structure coupled to an alignment pin for aligning the optical structure with the photonic integrated circuit.

In one or more embodiments, the substrate comprises a printed circuit board and a glass interposer, and the optical path extends through the substrate.

In one or more embodiments, the optical path comprises at least one optical fiber.

In one or more embodiments, the apparatus further comprises a connector positioned on the first side of the cold plate and coupled to the optical path. The connector may comprise an optical interface and an electrical interface for connection to a cable comprising at least one optical fiber and at least one electrical wire. The connector may be configured for receiving multi-phase pulse power from the cable on a plurality of electrical wires.

In one or more embodiments, the cold plate comprises an electrical path for transmitting power through the cold plate to an electronic integrated circuit attached to the substrate. The apparatus may further comprise a connector optically coupled to the optical path, a first power bridge interconnecting the connector to a fixed point-of-load (POL) module, and a second power bridge interconnecting the fixed POL module to a regulated POL module positioned on the first side of the cold plate for transmitting power to the electrical path. The first power bridge may be configured to transmit multi-phase pulse power to the fixed POL module.

In another embodiment, an apparatus generally comprises a connector for receiving or transmitting an optical signal, an optical path coupled to the connector and a photonic integrated circuit, and a cold plate interposed between the connector and the photonic integrated circuit. The optical path extends through the cold plate.

In yet another embodiment, a method generally comprises attaching a substrate to a cold plate, the substrate comprising at least one photonic die connected thereto, and creating an optical path through the cold plate and the substrate. An optical signal is transmitted to or from the photonic die through the optical path in the cold plate and the substrate.

Further understanding of the features and advantages of the embodiments described herein may be realized by reference to the remaining portions of the specification and the attached drawings.

Example Embodiments

The following description is presented to enable one of ordinary skill in the art to make and use the embodiments. Descriptions of specific embodiments and applications are provided only as examples, and various modifications will be readily apparent to those skilled in the art. The general principles described herein may be applied to other applications without departing from the scope of the embodiments. Thus, the embodiments are not to be limited to those shown, but are to be accorded the widest scope consistent with the principles and features described herein. For purpose of clarity, details relating to technical material that is known in the technical fields related to the embodiments have not been described in detail.

A power distribution system may be configured to deliver power from a point-of-load (POL) to an ASIC (Application-Specific Integrated Circuit) or other integrated circuit. As power requirements increase, additional thermal considerations may be needed. In package optic applications may present additional challenges including integration of optics and delivery of optical signals without impacting cooling systems.

One or more embodiments described herein provide integration of power and optics for delivery through a cooling plate to electronic and photonic integrated circuits (ICs) (die, ASIC, chip). As described in detail below, one or more electrical path and optical path are formed in the cold plate to allow power to pass from the POL to electronic components coupled to the substrate and optical signals to pass through the cold plate and substrate to photonic elements. The cold plate may comprise, for example, a power delivery block (e.g., PCB (Printed Circuit Board)) with one or more power vias for transferring power through the cold plate and one or more openings for defining an optical path. The optical path may comprise one or more optical elements (e.g., waveguide, mirror, or other optics) for transmitting an optical signal through the cold plate and directing the optical signal to or from the photonic integrated circuit. As described in detail below, the optical path may be coupled to a connector positioned on the cold plate for receiving or transmitting the optical signal. The connector may also be configured for receiving power (e.g., multi-phase pulse power), which may be delivered to the POL for distribution through the cold plate.

The embodiments described herein operate in the context of a data communications network including multiple network devices. The network may include any number of network devices in communication via any number of nodes (e.g., routers, switches, gateways, controllers, edge devices, access devices, aggregation devices, core nodes, intermediate nodes, power sourcing equipment, powered devices, or other network devices), which facilitate passage of data within the network. One or more of the network devices may comprise one or more power and optics distribution systems described herein. The network device may further include any combination of memory, processors, power supply units, and network interfaces.

Referring now to the drawings, and first toFIG. 1, a block diagram illustrating an example of power distribution through a POL power supply located on a board10is shown, in accordance with one embodiment. As described in detail below optics11is integrated with the power system and an optical path is created to transmit optical signals through the cold plate and substrate to or from a photonic chip13(photonic die, photonic integrated circuit, integrated optical circuit) integrating multiple photonic functions.

Power is delivered at element12to a plurality of POLs (POL modules (circuits), power components)14a,14c,14d,14e. In one example, pulse power at a voltage greater than 100V (e.g., 108V, 380V) or any other suitable voltage, is delivered to the fixed POL14a. The power source12may also deliver pulse power to POLs14c,14d, and14e(e.g., fixed POLs). In another example, the power source12delivers 54 VDC (or any other suitable voltage (e.g., intermediate bus voltage level selected based on overall system efficiency, routeability, and cost)) to POL modules14c,14d,14e. The fixed POL14atransfers power (e.g., at 54 VDC or other voltage) to the regulated POL (POL converter, POL regulator)14b, which distributes power to ASICs16(e.g., integrated circuit, die, chip, multi-chip module (MCM), and the like). As described below, the fixed POL14amay be connected to the regulated POL14bthrough a bus bar interconnect or any other suitable electrical connection. The regulated POL14bmay provide, for example, 150 amp or greater output. Each power connection may also include 10 Mbps (or any other data rate) communications. In the example shown inFIG. 1, power is delivered from the regulated POL module14bto the ASICs16via a voltage rail. Power may be provided to the ASICs16in a multi-drop arrangement, for example.

It is to be understood that the term “POL module” as used herein may refer to various types of POL configurations, including, for example, discrete POLs and modules or power delivery block-based voltage regulator designs. Also, it may be noted that the POLs may be single phase or multi-phase POLs that may work together to deliver one or more output.

System components (POL modules, cold plates, electronic and photonic package (substrate and die package)) are connected to the board10. The board10may comprise a printed circuit board or the components may be directly attached to sheet metal modules, a line card, or any other suitable support member. For example, a line card circuit board may be removed and the electronic package interconnected through fiber and copper connections at the ASIC edge.

As previously noted, pulse power may be supplied to one or more of the POL modules. The term “pulse power” (also referred to as “pulsed power”) as used herein refers to power that is delivered in a plurality of voltage pulses (sequence of voltage pulses)18ain which voltage varies between a very small voltage (e.g., close to 0V, 3V) during a pulse-off time19aand a larger voltage (e.g., ≥12V) during a pulse-on time19b. High voltage pulse power (high voltage pulses) (e.g., >56V, ≥60V, ≥300V) may be transmitted from power sourcing equipment (PSE) to a powered device (PD) for use in powering the powered device, whereas low voltage pulse power (low voltage pulses) (e.g., ˜12V, ˜24V, ≤30V, ≤56V) may be used over a short interval for start-up (e.g., initialization, synchronization, charging local energy storage, powering up a controller, testing, or any combination thereof). Pulse power transmissions may be through cables, transmission lines, bus bars, backplanes, PCBs, or power distribution systems, for example.

In one or more embodiments, the pulse power may be delivered in multiple phases (18b,18cinFIG. 1), with the pulses offset from one another between phases to provide continuous power. One or more embodiments may use multi-phase pulse power to achieve less loss, with continuous uninterrupted power with overlapping phase pulses to a powered device, as described in U.S. patent application Ser. No. 16/380,954 (“Multiple Phase Pulse Power in a Network Communications System”), filed Apr. 10, 2019, which is incorporated herein by reference in its entirety.

It is to be understood that the voltage, power, and current levels described herein are only provided as examples and power may be delivered at different levels (volts, amps, watts) than described herein without departing from the scope of the embodiments. Power may be received as ESP (Extended Safe Power) (also referred to as FMP (Fault Managed Power)) (e.g., pulse power, multi-phase pulse power, pulse power with fault detection and safety protection), PoE (Power over Ethernet), or in accordance with any current standard or future standard.

The term ESP (or FMP) as used herein refers to high power (e.g., >100 Watts (W)), high voltage (e.g., ≥56 Volts (V)) operation with pulse power delivered on one or more wires or wire pairs in a cable (e.g., Ethernet cable). In one or more embodiments, ESP includes fault detection (e.g., fault detection at initialization and between high voltage pulses), and pulse synchronization. As shown inFIG. 1, pulse power or multi-phase pulse power may be received at the fixed POL module14a. As described below with respect toFIG. 6, the pulse power may be received at a connector mounted on a cold plate and transmitted to the fixed POL module through an interconnect.

FIG. 2is a perspective schematic illustrating a connection between a fixed POL20and a regulated POL22, distribution of power through a cold plate25, and transfer of optical data through the cold plate and a substrate and die package21, in accordance with one embodiment. The fixed POL module20may provide input power to the regulated POL module22via an electrical connection24comprising, for example, a bus bar, wire, or other interconnect. For simplification, only one POL module22is shown connected to the cold plate25, however, any number of POL modules may be connected to the cold plate. Each POL may provide a single voltage rail or multiple voltage rails, as shown inFIG. 1. In the example shown inFIG. 2, an optical path23extends through the cold plate25and substrate for transmitting optical signals through the cold plate.

In one or more embodiments, an apparatus comprises the cold plate25comprising a first side27a(upper surface as viewed inFIG. 2) and a second side27b(lower surface) opposite to the first side, a photonic integrated circuit (chip)29connected to the substrate (e.g., printed circuit board, interposer, printed circuit board and interposer) positioned on the second side of the cold plate, and the optical path23extending through the cold plate25and the substrate (extending into the substrate and die package21) and optically coupled to the photonic integrated circuit for transmitting an optical signal between the first side of the cold plate and the photonic integrated circuit.

It should be noted that the terms lower, upper, bottom, top, below, above, horizontal, vertical, and the like, which may be used herein are relative terms dependent upon the orientation of the package and components and should not be interpreted in a limiting manner. These terms describe points of reference and do not limit the embodiments to any particular orientation or configuration.

Optical path23is created to allow light (indicated by arrow in optical path) to pass through the cold plate25and substrate21to reach the optical engine (photonic integrated circuit, chip, die)29. The optical path23may comprise, for example, one or more waveguides or an opening for receiving fiber optics. In one or more embodiments, the optical path23may be configured for light, laser written waveguides in glass, free space optics, or optical fiber, for example. A cutout may be made in the cold plate and substrate with passageway23inserted therein to link POL module22and bus bar24to the photonic chip29. In one example, optics are integrated with power delivery over bus bar24. The optical path23may be aligned and optically coupled to the photonics die29and module22as shown inFIG. 2, or may interconnect with a connector having interlocking features, as described below with respect toFIGS. 6 and 8A. The optical path23may be attached to the chip29using active or passive alignment processes and adhesive, such as an index matching epoxy, as described below with respect toFIG. 5. As described below with respect toFIGS. 4A-4D, the optical path may also be coupled to an edge, top, or bottom of the die29. Various coupling approaches may be used including, for example, edge coupling, vertical coupling, etc.

In one or more embodiments, the optical path23may be part of a dedicated cutout separate from the electronics as shown inFIG. 2. In one or more embodiments, the optical path and electrical path may be defined along the same cutout in the cold plate25. For example, a piece of glass may be laser patterned with waveguides and plated with metal vias to form a combined optical path and electrical path. Also, more than one optical path23may be formed in the cold plate25and substrate to communicate with one or more photonic die29.

In one or more embodiments, the optical path23may be constructed from an optical bulk material (e.g., SiO2or other suitable material) in which a plurality of waveguides and mirrors are defined, as described in U.S. patent application Ser. No. 16/546,084 (“Periscope Optical Assembly”), filed on Aug. 20, 2019, which is incorporated herein by reference in its entirety. The optical path23may comprise an optical path structure (e.g., periscope optical assembly) comprising, for example, one or more waveguide, mirror, lens, optical grating, filter, or any combination thereof. The optics may be defined by various processes in the bulk material based on the refractive index and the angle of light passing from one region to another. For example, a waveguide may be defined to confine light to a predefined path in the bulk material, whereas optics (e.g., a mirror) may redirect light received in one direction to a second direction. Other optics may have other effects on light carried in the bulk material, such as a lens focusing/converging or diffusing/diverging incoming light, an optical grating splitting and diffracting light into several beams, a filter removing, blocking, attenuating, or polarizing certain wavelengths of light, etc. Laser patterning may be used to define paths of the waveguide and a physical or chemical etching process may be used to form the mirror. The mirror may be defined, for example, as three-dimensional reflective structures within the bulk material or the mirror may be defined via a reflective surface treatment. It may also be noted that the optical path23may be formed from one piece or multiple pieces combined together as described below with respect toFIGS. 4A-4D. It is to be understood that these are only examples and other processes may be used to define optics within the optical path23or other optical components may be used, without departing from the scope of the embodiments.

An example of a fabrication process for creating the optical path23in the cold plate and substrate is described below with respect toFIGS. 4A-4D.

As previously described, in addition to providing the optical path23through the cold plate25, one or more electrical paths28may be created in the cold plate. As shown in the example ofFIG. 2, the cold plate25comprises a plurality of power delivery blocks26each comprising a plurality of power vias (electrical paths)28for transmitting power through the cold plate, from the POL module22to an electronic package21(substrate and die package) (described below with respect toFIG. 3). Power is transmitted from a first side of the cold plate25(e.g., upper surface27aas shown inFIG. 2) to a second side (e.g., lower surface27bas shown inFIG. 2) of the cold plate opposite and generally parallel to the first side. In one or more embodiments, the power delivery block26comprises a small (miniature) power printed circuit board. Based on the application, other components may also be inserted into the cold plate25or strategically placed cutouts may be used.

The power delivery block26comprises a plurality of through holes (vias)28, which extend through the entire thickness of the power delivery block (as shown in phantom inFIG. 2) and are plated along their interior surfaces. The through hole may, for example, be created using a drilling process and plated with a metallic material (e.g., copper or any conductive or metallic layer). The plating may effectively cover the barrel of the hole and create the electrical path28through the cold plate25.

The term “power delivery block” as used herein may refer to any block of thermal and conductive material in which electrical paths (e.g., power vias) may be formed to allow for the passage of power directly through the cold plate25. Although the term “printed circuit board” is used herein as an example of a substrate for the power delivery block26, in other implementations the PCB may be replaced with other substrates (e.g., ceramic circuit boards) or other elements. Also, non-printed circuit boards may be used for the power delivery block26. For example, a piece of glass may be laser patterned with waveguides and plated with metal vias to form a combined optical path and electrical path. Also, as previously noted, other components in addition to or instead of the PCB may be inserted into the cold plate25.

The cold plate25may comprise, for example, liquid, gas, or multi-phase (multi-phase cold plate) based cooling. The through power vias28may deliver 10 amps per tube, for example, and may be cooled by the cold plate25. In one or more embodiments, the cold plate25is formed with one or more openings for insertion of one or more power delivery blocks26, which may be, for example, press fit into the cold plate25. An epoxy resin or adhesive fill may be used to press and position the power delivery block26within the cold plate25. The epoxy resin may be used to account for tolerances between the power delivery block26and cold plate opening. If the cold plate25utilizes cooling tubes or reservoirs, these are routed or positioned around the power delivery block and optical path openings. The cold plate25keeps a temperature rise low for the power vias28, thereby maximizing current transfer from the POL22to the substrate and die package. In one example, the cold plate25is configured with multiple internal zones to maintain optical temperature below 75 degrees Celsius. It is to be understood that the cold plate and temperature described herein are only examples and other designs may be used to maintain cooling at different temperatures.

In one or more embodiments, the power block, power vias, and cold plate may be configured as described in U.S. patent application Ser. No. 16/743,371 (“Power Distribution from Point-of-Load With Cooling”), filed Jan. 15, 2020, which is incorporated herein by reference in its entirety.

The power delivery blocks26and vias28formed therein extend through the cold plate25to provide power to the attached electronic package (substrate and die package)21. For simplification, only a portion of the power delivery blocks26and vias28are shown in phantom extending through the cold plate25. Also, the substrate and die package21is shown as a single block structure, but it is to be understood that the package may comprise one or more substrates with any number of components (e.g., electronic integrated circuit, ASIC, photonic integrated circuit, optical engine, die, chip, chiplet, FAU (Fiber Attachment (Array) Unit), CAU (Copper Attachment (Array) Unit)) attached thereto, as described below with respect toFIG. 3.

In one or more embodiments, an additional cold plate31may be used, with the substrate and die package21interposed between the two cold plates25,31to provide additional cooling. It may be noted that use of the second cooling plate31is optional based on power and cooling requirements.

Also, it is to be understood that the cold plate may comprise any number of individual cold plates. For example, the cold plate may comprise two or more smaller cold plates with one or more of the power delivery block, electrical path, or optical path interposed therebetween.

In addition to passing power through the power delivery block26, communications (e.g., control plane communications) may also pass through the power delivery block. In one or more embodiments, control communications for the regulated POL and for the ASIC to a system FPGA (Field-Programmable Gate Array) may pass through the cold plate25or through ribbon cables. In one or more embodiments, communications may pass through communication vias (not shown) formed in the power delivery blocks, which may include both power vias and communication vias or only communication vias. In one example, lower speed communications may pass through the POL (e.g., 200 Mbps range). The cold plate25may include any combination of power delivery blocks with power vias, communication vias, or optical paths. Control plane communications may also be provided through separate communications elements (e.g., via ribbon cable or other means), which may be used to move control communications in and out of the package. In one or more embodiments full speed PCIe (Peripheral Component Interconnect express) or faster may be used. The cold plate25may be connected to any number or combination of POL modules22and communication modules.

It is to be understood that the configuration shown inFIG. 2is only an example, and the cold plate may include any number, combination, or arrangement of power blocks26, optical paths23, and communication paths.

Referring now toFIG. 3, a cross-sectional schematic illustrates an apparatus comprising a substrate41having a first surface41aand a second surface41bopposite to the first surface, integrated circuits (one or more die (chip))33,39attached to the first surface of the substrate, and a cold plate35attached to the second surface of the substrate and comprising an electrical path (e.g., power via)38extending therethrough for transmitting power from a power component (e.g., POL module)32to an electronic integrated circuit33and optical paths48for transmitting one or more optical signals to or from a photonic integrated circuit (photonic chip, optical engine)39. The term “substrate” as used herein may refer to an electrical board, ceramic board, or an element formed from any other suitable material. As described below, the substrate may also comprise an interposer (e.g., glass element laser patterned with waveguides and plated with metal vias to form a combined optical path and electrical path).

Bus bars34are shown connected to a multi-zone POL30(e.g., with DC power to rail voltage) with POL modules32attached to the cold plate35and configured to distribute power from the POL modules to an electronic and optical package comprising the substrate41, the electronic integrated circuit33(ASIC, NPU (Network Processing Unit), die, chip), and two optical engines (photonic integrated circuits)39(SerDes (Serializer/Deserializer) chiplet) attached to the substrate. The electronic and optical package (also referred to herein as a substrate and die package) may comprise one or more integrated circuit, ASIC, NPU, MCM, die, chip, chiplet, processor, electronic component, or photonic component attached to one or more substrates. In the example ofFIG. 3, the substrate and die package includes the substrate41, NPU33, optical engines39and FAU/CAU40. It is to be understood that this is only an example and the substrate and die package may include any number of components in any arrangement. The FAU/CAU40may be attached to a lower surface of the optical engine39(as shown inFIG. 3) or positioned on an upper surface or side of the optical engine39, or may be removed if optics and power are transmitted by another means. In the example ofFIG. 3, a second cold plate37is thermally coupled to the NPU33through a thermal conductor (interposer)49. The thermal conductor (or a plurality of thermal conductors) may be positioned across multiple die. One or more embodiments may also include an optional lid between the multi-chip module and the cold plate37.

In the example shown inFIG. 3, two optical paths48extend through the cold plate35and substrate41and are optically coupled to a side of the photonic chips39. As described below with respect toFIGS. 4A-4D, the optical path48may also be coupled to the photonic chip39along a lower edge of the chip. As previously described with respect toFIG. 2, optical signals may be transmitted along with power at the POL module32.

As previously described, the cold plate35includes one or more power delivery blocks36(e.g., PWR PCB) inserted into the cold plate, with one or more electrical paths (power vias)38formed therein. In one or more embodiments, the power delivery blocks36are formed separately from the cold plate35and inserted into openings46formed in the cold plate for receiving the blocks. As discussed above, an epoxy resin or adhesive fill may be used to press and position the power delivery blocks36within the openings46in the cold plate35.

The substrate41may comprise traces43and pads45embedded within or deposited on the substrate for connection with the power vias38and die33,39. Etching, deposition, bonding, or other processes may be used to form the traces and pads. The substrate41may be bonded to the cold plate35using solder processes, as well known by those skilled in the art.

It is to be understood that the components and arrangement shown inFIG. 3is only an example and other types or number of components with different sizes and arrangement, or additional components may be used without departing from the scope of the embodiments. For example, one or more integrated circuits may be positioned on an upper surface of the cold plate35(side opposite the substrate41). In one or more embodiments, the cold plate35may only include the optical path48with electrical power being supplied to the electronic integrated circuit (NPU)33via another path.

Referring now toFIGS. 4A-4Da fabrication process for the optical path is shown, in accordance with one embodiment. In this example, an interposer (e.g., glass interposer)51is positioned between the substrate41and photonic integrated circuit39. The glass interposer51may include any number of optical or electrical connections between the substrate41and the photonic integrated circuit39. The connections may include, for example, one or more power connections (e.g., conductive vias)44, one or more high-speed signal connections, or any combination thereof. The interposer51may be formed from an optically transmissive material, such as a silicate glass, quartz, or any other suitable material. The interposer51may be coupled with the substrate41through any suitable surface mounting technique. Solder balls may be attached to the interposer51and couple with circuitry of the substrate41in a ball grid array, for example. The photonic chip39is attached to the interposer51through any suitable means (e.g., bonding). In one or more embodiments, the photonic integrated circuit39may be coupled with the interposer51as described in U.S. Pat. No. 10,393,959 (“Photonic Integrated Circuit Bonded with Interposer”), issued Aug. 27, 2019, for example. An electronic integrated circuit53is also shown coupled to the photonic integrated circuit39in the example shown inFIGS. 4A-4D.

It is to be understood that the term “substrate” as used herein may refer to multiple elements (e.g., printed circuit board41and interposer51) or a single element or board.

Referring first toFIG. 4A, a cross-sectional schematic is shown illustrating a first opening50passing through the cold plate35and substrate41. As described below with respect toFIG. 4B, opening50is used to insert an optical path structure for communication with the photonics chip39along an edge of the chip. A second opening52is shown extending through the cold plate35, substrate41, and interposer51for receiving an optical path structure for communication with the photonic chip39through an upper surface of the chip. For simplification, the schematic is shown with the cross-section passing through the openings50,52, without the material behind the openings shown. In one or more embodiments, vertical or edge coupling may be used to attach optics to the photonic die39. It is to be understood that while placement of two different optical paths are shown inFIGS. 4A-4Dfor illustration purposes, only one of the paths may be used to provide an optical path through the cold plate35and substrate41. In one or more embodiments, the interposer51may be shortened so that the opening52passes through the cold plate35and substrate41, and along a side the interposer51. Also, in one or more embodiments, an optical path may extend through the cold plate35and along an outer edge of the substrate41and interposer51and couple with a lower side of the photonic die39through the use of optics redirecting light towards the lower side of the die.

The optical engines (photonic integrated circuits, photonic dies, photonic chips)39may be first attached to the interposer51and substrate41, which is then attached to the cold plate35. The cutouts50,52may then be formed in the cold plate35, substrate41, and interposer51to accommodate the optical path. In one or more embodiments, a sleeve (not shown) may be inserted into the openings, which may be formed using any suitable process.

As shown inFIG. 4B, optical paths (optical path structures)48a,48bare positioned in the openings52,50and attached to the photonic die39to optically couple the photonic die to the optical path. The optical path48a,48bmay be attached using active alignment, precise passive alignment, UV/thermal cure epoxy, or any other suitable process. Further details of an attachment method are described below with respect toFIG. 5. Depending on where the optical connection is located on the die39(e.g., side or top as viewed inFIGS. 4A-4D) and whether the light comes out on a surface or from the side of the die, the optical path may attach to the surface of the die (as shown for optical path48a) or one of the edges (as shown for optical path48b). The optical paths48a,48beach comprise a waveguide55a,55bdefined to confine light to a predefined path. Optical path48bincludes a mirror (optics)56bfor redirecting light received in one direction to a second direction. As previously noted, each optical path48a,48bmay comprise other optical components such as a lens for focusing/converging or diffusing/diverging incoming light, an optical grating for splitting and diffracting light into several beams, or a filter for removing, blocking, attenuating, or polarizing certain wavelengths of light.

As shown inFIG. 4C, in order to simplify manufacturing, the optical path48a,48bmay plug in or connect to another optical path (e.g., periscope/routing structure)57to combine all of the optical signals. Optical path structure57includes waveguide55cand mirrors56c,56dfor redirecting light from the optical paths48a,48bto an optical connector54(FIG. 4D). Strain relief epoxy or filler material may be used to further support the optical path structures. Index matching epoxy may also be used in the optical path to improve coupling at the connections between the optical paths.

FIG. 4Dillustrates the completed assembly with the POL modules32, optical connector54, and remaining mechanical components attached to complete the package. Optical path57may include additional mirrors (not shown) to redirect light into the connector54.

It is to be understood that the optical paths shown and described herein are only examples and the structures may be configured or manufactured different than described or shown without departing from the scope of the embodiments. As previously noted, multiple optical paths may be attached or plugged together to create an optical path between an upper surface of the cold plate and the photonic die. The optical path may be formed from various materials (e.g., glass, heat-resistant polymers, etc.) using various processes. In one example, laser patterning of glass may be used to write waveguides and precisely write and etch mechanical features such as plugs for interlocking slots (described below with respect toFIG. 5). Laser patterning may also be used to pattern other glasses such as gorilla glass (chemically strengthened glass) or flexible glass. As previously noted, mirrors, lenses, or other optics may also be patterned into the optical path. An electrical via with plated metal may also be created in the laser patterned structure to allow electrical signals to be routed in the same structure as the optical signals.

FIG. 5illustrates an example of an optical path59with an etched mirror61and an opening63afor use in aligning the optical path with an interposer and photonic chip assembly62. The optical path59includes a waveguide60, mirror61, and opening63afor receiving the alignment pin63bfor attachment to the interposer and photonic chip assembly62. An index matching epoxy64may be used to hold the plug in place and ensure coupling between the plug63band the optical path (e.g., periscope)59. Also, more than one alignment pin may be used. As previously described, active alignment may be used to attach the optical path59with the alignment pin63bused for coupling the optical path to the interposer or another optical path. For embodiments in which edge coupling may not be used, the optical path may be attached by vertical or evanescent coupling.

In one or more embodiments, optical signals and pulse power may be received from a connector inserted into a connector cage coupled to the optical path as shown inFIG. 6. As previously described with respect toFIG. 2, the fixed POL module20is coupled to the regulated POL module22via the power bridge24. A high power (ESP, pulse power) bridge66connects the fixed POL20to a connector (connector cage)67positioned on a first (upper) side of cold plate65. Optical signals and are received at optical interface74aand power (e.g., multi-phase pulse power) is received at electrical interfaces74b,74c). One or more optical signals are transmitted to or from the photonic chip29via optical path68passing through the cold plate65and substrate71, as previously described with respect toFIG. 2. The optical path68optically couples the optical interface74aand photonic chip29. The multi-phase pulse power is transmitted from the electrical interfaces74b,74cto the fixed POL20via the high-power bridge66and is used to power the regulated POL via the power bridge24. In one example, the multi-phase pulse power may be transmitted from the electrical interfaces74b,74cto the high-power bridge66via an electrical path integrally formed with the optical path68or by other means through the connector (connector and connector cage)67. As previously described with respect toFIG. 1, the multi-phase pulse power may be modified before being transmitted from the fixed POL module20to the regulated POL module22.

FIG. 7illustrates details of the optical and electrical connector, in accordance with one embodiment. As previously described, a connector77is coupled to the optical path68. The connector77includes an optical interface75and electrical interfaces76. In one or more embodiments, the optical interface75may be configured for mating with an MPO (Multi-fiber Push On) type connector79, as described below with respect toFIGS. 8A and 8B. In one example, optical interface75comprises a photonic element (e.g., photonic die). In the example shown inFIG. 7, the electrical interfaces76are configured for receiving three-phase pulse power (P1, P2, P3). A hybrid cable78comprising one or more optical fibers and electrical wires (e.g., two optical fibers and three-pair copper) is coupled to cable connector79for mating with the connector77mounted on the cold plate.

It is to be understood that the interface configuration shown inFIG. 7is only an example and that the connector77may be configured for coupling with any number of optical fibers or electrical wires (wire pairs) for receiving any number of phases of pulse power and receiving or transmitting any number of optical signals.

In one or more embodiments, the optical portion of the connector assembly may be configured as shown and described in U.S. patent application Ser. No. 16/544,699 (“Connection Features for Electronic and Optical Packaging”), filed Aug. 19, 2019, which is incorporated herein by reference in its entirety. The connector may be modified to include electrical power input (e.g., multi-phase pulse power as described above with respect toFIG. 7).

FIGS. 8A and 8Billustrate an example of a clamp assembly configured for use with an MPO connector. It is to be understood that MPO is only one example and the clamp assembly may be used with other types of optical connectors (e.g., LC connector). As described below, a clamp structure of the connector assembly may be used to provide an electrical contact between the optical and electrical cable and a photonics package. The optical signals are transmitted through the optical fiber, while the clamp provides contact for electrical signals. The clamp and electrical connection may be integrated into a photonics die by using the clamp to provide an electrical contact.

FIG. 8Aillustrates an exploded view of a connector assembly, in accordance with one embodiment. The connector assembly includes an optical and electrical connector, generally indicated at80, that is mounted on the cold plate, as previously described with respect toFIG. 6, and a cable connector86, which is used to couple the hybrid cable to the package. The optical and electrical connector80comprises a frame81, a photonic element (e.g., photonic integrated circuit)82mounted in the frame, an optical adapter84, and a fastener (clamp)83a. The photonic element82optically interfaces with the optical adapter84to carry optical signals to the photonic element82from the cable connector86via optical fibers. The photonic element82may include one or more waveguides connected to an optical component integrated within the photonic element. The frame81includes openings85for receiving attachment fingers83b(pegs) of the fastener83a. The openings85provide a mechanical connection point for the fastener83aincluding the mechanical attachment portion83b. As previously noted, the fastener (clamp)83amay provide an electrical connection between the cable connector86coupled to one or more wire pairs89and the optical and electrical connector80.

The cable connector86provides an optical connection between optical fibers88and the optical features on the photonic element82and an electrical connection between electrical wires89in the cable and an electrical interface on the connector80. The cable connector86may include alignment pins87, which may assist in the mechanical alignment of the optical connector to the frame81and photonic element82. As previously noted, the cable connector86may comprise an MPO connector modified to provide an electrical connection between electrical wires89in the hybrid cable and the connector80. Electrical wires89, which are received in a hybrid cable comprising the optical fibers88and electrical wires, may be coupled to the cable connector at various locations. For example, as shown inFIG. 8A, the electrical wires89may enter the cable connector86along with the optical fibers88or may be received on one or more edge portions of the cable connector.

The assembled optical and electrical connector80and cable connector86are shown inFIG. 8B. In this example, the electrical wires89are shown offset from the optical fibers88with an electrical connection formed between the electrical wires and the fastener83a. As previously noted, an MPO connector may be modified to receive the electrical wires or the electrical wires may be coupled independently to the connector80(e.g., electrically coupled to the clamp assembly).

It is to be understood that the connector assembly shown inFIGS. 8A and 8Bis only an example and other types of optical and electrical connectors may be used, without departing from the scope of the embodiments.

FIG. 9is a flowchart illustrating an overview of a process for implementing the optics distribution system, in accordance with one embodiment. At step90, the substrate and photonic die package are attached to the cold plate (FIGS. 4A and 9). One or more optical paths are created through the cold plate (or cold plate and substrate) (step92) (FIGS. 4B and 9). As previously described, one or more optical path structures (e.g., periscope optical assembly) may be inserted into openings formed in the cold plate and attached to one or more other optical structures to form the optical path between the optical connector positioned on a first side (upper side) of the cold plate and the photonic die (FIGS. 4C and 4D).

It is to be understood that the process shown inFIG. 9and described above is only an example and steps may be added, modified, combined, or reordered without departing from the scope of the embodiments.

Although the apparatus and method have been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations made to the embodiments without departing from the scope of the embodiments. Accordingly, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.