Foldable and modular optical interconnect modules for high-density optical interconnects

Abstract

Optical interconnect modules and systems for high-density applications, including foldable optical interconnect modules having connector interfaces configured to provide electrical connections to a host printed circuit board, flexible circuits for routing electrical signals, optical carrier assemblies integrating electrooptic components, and thermal management structures providing thermal dissipation paths are described. Also disclosed are modular optical interconnect modules employing stackable sub-modules integrating optical elements, printed circuit board assemblies, and thermal management interfaces, enabling scalable configurations with vertical fiber routing. The optical interconnect modules and arrangements support high-speed signal conversion between electrical and optical domains while maintaining thermal efficiency through direct coupling to external cooling systems. Methods of assembling and using the optical interconnect modules in high-density configurations around processing units are also provided, including techniques for electrical signal distribution, optical signal routing, and thermal management optimization.

Description

Attorney Docket No. P3153-PCTFOLDABLE AND MODULAR OPTICAL INTERCONNECT MODULES FOR HIGH-DENSITY OPTICAL INTERCONNECTSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to US Prov. App. No. 63 / 744,293 filed on January 12, 2025 and US Prov. App. No. 63 / 774,703 filed on March 19, 2025, both of which are incorporated herein by reference in their entirety.

[0002] The “Si-Fly™” connector or Si-Fly™ connector interface, as referenced throughout this document, corresponds to the connector described in International Patent Application No. PCT / US2023 / 031924, filed on September 1, 2023 (published as WO 2024 / 050137 Al), entitled “Electrical Connector Apparatus and Method”, which is incorporated herein by reference in its entirety.FIELD

[0003] The present disclosure relates to the field of optical interconnect modules (e.g. optical transceivers, optical transmitters or optical receivers) and high-speed data interconnect systems, specifically focusing on scalable, thermally managed designs suitable for high-bandwidth and high-density applications.BACKGROUND

[0004] High-performance computing and Al (artificial intelligence)-related applications demand compact, scalable optical interconnect modules capable of delivering high bandwidth while effectively managing heat dissipation. The increasing need for higher data rates and greater interconnect density places significant strain on conventional optical interconnect module designs, such as optical transceivers, optical receivers, and optical transmitters. These traditional approaches often face limitations in handling the thermal loads generated in high-power environments, leading to higher bit-error rates and reduced reliability. Furthermore, as channel counts grow, scalability becomes a critical challenge, exacerbated by difficulties in preservingAttorney Docket No. P3153-PCTsignal integrity in densely packed configurations. High-speed operations further compound these issues by increasing vulnerability to noise and crosstalk. These persistent challenges underscore the pressing need for innovative solutions that can address the technical demands of modem high-performance applications.

[0005] International Patent Application No. PCT / US2023 / 031924, filed on September 1, 2023 ("the '924 application"), describes a foundational electrical interconnect technology known as the Si-Fly™ connector system. The '924 application, which is hereby incorporated by reference in its entirety, discloses a connector architecture that utilizes a unique "egg-crate" shield structure with ground planes separating differential signal pairs. This architecture enables extremely dense signal routing while maintaining signal integrity at high frequencies. In some embodiments, the Si-Fly™ connector achieves a differential pair density of up to 256 pairs per square inch while supporting data rates up to 224 Gbps PAM4.

[0006] The Si-Fly™ connector interface described in the '924 application incorporates several features that enable its high performance. The mating interface includes a plurality of interlocking plates that define precisely controlled cavities for the differential signal pairs. These cavities are sized and shaped to maintain consistent impedance and minimize crosstalk between adjacent channels. Ground contact elements positioned within the cavities provide proper signal return paths and shielding. The connector's design provides flexibility for different implementations, potentially enabling both electrical and hybrid electrical-optical solutions that can be compatible with its mechanical interface and form factor.

[0007] The ‘924 application discloses the Si-Fly™ connector interface enabling an electrical connection between a host substrate, such as a printed circuit board or integrated circuit die package substrate, and a plurality of electrical cables. However, as system designers push for ever-higher bandwidth density and signal transmission distance, all electrical systems can no longer meet the system requirements. As a result, system designers are turning to optical solutions with an optical interconnect module either co-packaged with the IC die or mid-board mounted adjacent the IC die package. In either case, the close proximity of the optical interconnect module to the IC die poses challenges in managing the thermal loads experienced by the optical interconnect module. This has created a need for novel optical interconnect module architectures that canAttorney Docket No. P3153-PCTpreserve the electrical and mechanical benefits of the Si-Fly™ connector interface while enabling the higher data transmission rates and longer transmission distances of an optical interconnection.Attorney Docket No. P3153-PCTSUMMARY

[0008] Embodiments of the present application are directed to leveraging a connector interface (such as a Si-Fly™ connector interface) with an optical interconnect module to enable high data transport speeds over longer distances.

[0009] In particular, methods and devices addressing the above-mentioned challenges and issues encountered in the design of optical interconnect modules such as transceivers are presented. The disclosed devices can be used to optimize footprint usage, thermal performance, and scalability, making them ideal for dense deployment in advanced processing systems.

[0010] The described teachings include a foldable optical interconnect module for compact, thermally optimized applications a modular optical interconnect module for scalable high-channel-count configurations, and methods for assembling and connecting such modules. The foldable optical interconnect module utilizes flexible circuitry and heat spreaders to achieve a folded design that facilitates optical connection in an open state and minimizes the substrate footprint in a closed state. The modular optical interconnect includes stackable sub-modules, each integrating optical elements, PCB assemblies, and heat dissipation components forming a common thermal interface, allowing vertical fiber egress and efficient assembly.

[0011] According to a first aspect, a foldable optical interconnect module comprises a connector interface configured to provide electrical connections to a host PCB, a flexible circuit for routing electrical signals extending to at least one optical carrier assembly integrating electrooptic components, a least one optical block having an alignment interface for optical signal routing, and at least one heat spreader providing a thermal dissipation path to an external heat dissipating surface.

[0012] According to a second aspect, a modular optical interconnect module comprises multiple stackable sub-modules each including integrated optical elements, PCB assemblies, and heat spreaders, a common thermal interface formed by the heat spreaders of the plurality of stackable sub-modules arranged adjacent to one another, interconnect elements for power and signal distribution, and fiber routing structures enabling vertical fiber egress.Attorney Docket No. P3153-PCT

[0013] According to a third aspect, an optical interconnect system comprises a connector interface comprising an array of cavities and configured to provide electrical connections to a host printed circuit board (PCB), electrooptic components, a thermal management structure, and a signal distribution structure comprising electrical pathways, optical fiber pathways perpendicular to the electrical pathways, and thermal conduction pathways, all arranged within the connector interface footprint.

[0014] According to a fourth aspect, a method of manufacturing an optical interconnect module comprises providing a connector interface, arranging electrooptic components, implementing thermal management structures, establishing signal routing, and configuring all components within the connector interface footprint.

[0015] According to a fifth aspect, an optical interconnect system comprises a connector base configured to mate with a host circuit board, multiple optical conversion modules each comprising a connector interface, electrooptic components and associated thermal management structures, signal routing elements coupling the connector base to the optical conversion modules, and a unified thermal interface coupling to an external cooling system.

[0016] According to a sixth aspect, a high-density optical interconnect arrangement comprises multiple optical interconnect modules interfacing with a processing unit, a common cooling interface, signal routing structures, and fiber routing structures preventing interference between adjacent modules.

[0017] According to a seventh aspect, a foldable optical interconnect module comprises a base portion with an electrical connector interface, a flexible circuit portion, an optical conversion portion with electrooptic components, and a thermal dissipation portion, where the flexible circuit enables folding while maintaining electrical connectivity.

[0018] According to an eighth aspect, a foldable optical interconnect module comprises a connector interface, an optical carrier assembly, flexible circuitry, heat spreaders, and an optical interface block with a standardized connector interface for mateable / unmateable fiber connections.Attorney Docket No. P3153-PCT

[0019] According to a ninth aspect, an electrical interconnection system comprises a housing with cavities in an array, ground shield structures, electrical contacts, and connection elements configured to mate with either an optical conversion module or a cable connector.

[0020] According to a tenth aspect, an optical interconnect system comprises a host PCB, a connector base mounted on the host PCB and comprising an array of high-speed differential signal contacts, auxiliary power and control cables separate from the connector base, and an optical interconnect module comprising a connector interface configured to mate with the connector base, electrooptic components, athermal management structure, high-speed signal pathways coupled to the connector interface, and power and control pathways coupled to the auxiliary power and control cables.

[0021] According to an eleventh aspect, a method of using an optical interconnect module comprises receiving electrical signals, performing electrical-to-optical conversion, outputting optical signals perpendicular to the electrical interface, and transferring heat to an external cooling system.

[0022] According to a twelfth aspect, a method of using a modular optical interconnect system comprises arranging multiple signal conversion modules in a stack, distributing electrical signals between modules, routing optical media vertically, and transferring heat through a shared thermal interface.

[0023] According to a thirteenth aspect, a method of using multiple optical interconnect modules comprises positioning modules around a processing element, routing optical media to prevent interference, and thermally coupling components to a shared thermal distribution element.

[0024] According to a fourteenth aspect, an optical interconnect module comprises an optical interconnect portion comprising electrooptic components, a connector interface configured to mate with a host PCB, and an auxiliary cable separate from the connector interface, wherein the auxiliary cable carries power and control signals.

[0025] According to a fifteenth aspect, an optical interconnect system comprises; a host PCB, a connector base mounted on the host PCB, and an optical interconnect module configured to mateAttorney Docket No. P3153-PCTwith the connector base, the module including electrooptic components for signal conversion, a connector interface, and an auxiliary cable carrying power and control signals.

[0026] According to a sixteenth aspect, a high-density interconnect arrangement comprises an integrated circuit (IC) die mounted on an IC package substrate, wherein the IC package substrate is mounted on a host printed circuit board (PCB), a plurality of interconnect modules co-packaged with the IC die, each configured to mate with the IC package substrate via a high-speed interface, the interconnect modules comprising electrical interconnect modules and / or optical interconnect modules arranged in a pattern along the sides of the IC die, and a plurality of cables extending from each interconnect module to carry optical or electrical signals, wherein the cables extend primarily from one side of each respective interconnect module.

[0027] According to a seventeenth aspect, an optical interconnect module comprises a first optical interface configured to provide optical communication between a first electrooptic component and a first group of optical fibers, a second optical interface configured to provide optical communication between a second electrooptic component and a second group of optical fibers, wherein the first optical interface is independently connected to the first group of optical fibers and the second optical interface is independently connected to the second group of optical fibers, a first heat spreader in thermal communication with the first electrooptic component, and a second heat spreader in thermal communication with the second electrooptic component, wherein a top surface of the first heat spreader and a top surface of the second heat spreader form a common thermal interface configured to dissipate heat from the first electrooptic component and the second electrooptic component to an external heat sink.

[0028] According to an eighteenth aspect, an optical interconnect module comprises a mateable / unmateable electrical interface comprising an array of differential signal pairs with each differential signal pair in a cavity surrounded by a ground shield, a first electrooptic component in electrical communication with a first portion of the array of differential signal pairs configured to perform an optical-to-electrical or electrical-to-optical conversion, a second electrooptic component in electrical communication with a second portion of the array of differential signal pairs configured to perform an optical-to-electrical or electrical-to-optical conversion, wherein the second electrooptic component is spatially separated from the first electrooptic component, and aAttorney Docket No. P3153-PCTcommon thermal interface configured to dissipate heat from the first electrooptic component and the second electrooptic component.

[0029] According to a nineteenth aspect, a method of making an optical connection to an optical interconnect module comprises placing the optical interconnect module in an open position, connecting a fiber ferrule to an optical interface of the optical interconnect module, and folding a flexible circuit of the optical interconnect module to place the optical interconnect module in a closed position.

[0030] Further aspects of the disclosure are provided in the description, drawings and claims of the present application.Attorney Docket No. P3153-PCTDESCRIPTION OF THE DRAWINGS

[0031] Figs. 1A-1C show an exemplary foldable optical interconnect module according to an embodiment of the present disclosure. In particular, Fig. 1A illustrates the interconnect module in its folded, operational configuration where optical fibers exit perpendicular to the Si-Fly™ connector’s mating direction and a flat upper surface is presented for thermal interface attachment, while Fig. IB depicts the interconnect module in an open configuration that enables access for the mating and unmating of optical connectors. Fig. 1 C shows in more detail the interaction of various elements associated with the optical interconnect module.

[0032] Figs. 2A-2D show an exemplary modular optical interconnect module according to an embodiment of the present disclosure. In particular, Fig. 2A provides a perspective view of the complete assembly with vertically-arranged optical fibers, while Figs. 2B and 2C present two-dimensional and three-dimensional cross-sectional views respectively, illustrating the internal arrangement of the stackable sub-modules and their thermal and electrical interconnections. Fig.2C shows a rotated view of the optical interconnect module for clarity of illustration; in actual operation, the printed circuit board is generally mounted horizontally to the host system, with the Si-Fly™ connector mating vertically to the board and the optical fibers exiting vertically upward from the module. Fig. 2D illustrates both vertical dashed lines showing RF ground plane extension from the Si-Fly™ connector, and horizontal dashed lines representing power and control signal distribution (including low-speed signal returns and power returns) for housekeeping functions.

[0033] Fig. 2E shows a sub-module of a modular optical interconnect module according to an embodiment of the present disclosure.

[0034] Fig. 2F shows an electrical module for the power, control signals, and their return paths according to an embodiment of the present disclosure.

[0035] Fig. 2G shows a perspective view of a sub-module heat spreader according to an embodiment of the present disclosure.

[0036] Fig. 2H shows placement of the sub-module heat spreader on a back side of the PCB assembly according to an embodiment of the present disclosure.Attorney Docket No. P3153-PCT

[0037] Fig. 3 shows an exemplary optical interconnect system in accordance with an embodiment of the present disclosure.

[0038] Fig. 4A shows a schematic cross-sectional view of co-packaged optical interconnect modules with lateral fiber egress according to an embodiment of the present disclosure.

[0039] Fig. 4B shows a schematic cross-sectional view of co-packaged optical interconnect modules with vertical fiber egress according to an embodiment of the present disclosure.

[0040] Fig. 5A is a simplified perspective view of a high-density interconnect module arrangement showing multiple interconnect modules co-packaged with an IC die on an IC package substrate, arranged in a rectangular pattern.

[0041] Fig. 5B is a perspective view of a high-density interconnect module arrangement showing a "single-connector" configuration wherein all signals — both high-speed and power / control signals — are routed through the same connector.

[0042] Fig. 5C is a perspective view of a high-density interconnect module arrangement showing a configuration wherein high-speed signals are routed through one connector, while power and control signals are routed through a separate auxiliary connector.

[0043] Fig. 5D is a perspective view of a high-density interconnect module arrangement showing an "auxiliary-cable" configuration wherein high-speed signals pass through a main connector, while a dedicated ribbon cable extends from the module for power and control signals.

[0044] Fig. 5E is a zoomed-in top view of the interconnect module arrangement revealing the electrical contacts of a connector, with one module removed to show details.

[0045] Fig. 6 shows a cooling system for a plurality of optical interconnect modules according to an embodiment of the present disclosure.

[0046] Fig. 7 is an exploded view of Fig. 6 showing a cooling system for a plurality of optical interconnect modules according to an embodiment of the present disclosure.Attorney Docket No. P3153-PCTDETAILED DESCRIPTION

[0047] Figs. 1A-1C show an exemplary foldable optical interconnect module (100) according to an embodiment of the present disclosure. As detailed later, Figs. 1A-1B correspond to an open and a closed configuration of the interconnect module, respectively. Fig. 1C is a diagram illustrating more in detail the interconnection of various elements associated with foldable optical interconnect module (100). Foldable optical interconnect module (100) includes a base portion with a Si-Fly™ connector interface (101), a flexible circuit (102) extending from the base portion. The flexible circuit (102) may be symmetric about a plane of symmetry (113). Each side of the flexible circuit (102) may include an optical conversion portion comprising an optical carrier assembly (103 A and 103B) with electrooptic components and alignment features providing a multifiber optical interface for precise optical signal routing, and a thermal dissipation portion comprising heat spreaders (104A and 104B). Each optical carrier assembly (103A and 103B) may be configured to mate with a plurality of optical fibers (112A and 112B) supported by a fiber ferrule (110A and HOB). The foldable optical interconnect module (100) may be mated to an underlying substrate (not shown in Figs. 1A-1C) by placing the module above the substrate and moving the module towards the substrate in a mating direction as shown in Fig. 1A. During operation optical signals may propagate through the optical fibers (112A and 112B) to and from the foldable optical interconnect module (100). This embodiment is designed to achieve compactness and thermal efficacy for dense optical interconnections.

[0048] Disposed at the base of the foldable optical interconnect module (100), the Si-Fly™ connector interface (101) provides the primary electrical data connection to a host PCB or an IC package substrate (not shown but disposed underneath foldable optical interconnect module (100)). In an embodiment, such a connector interface includes an 8x8 array of high-speed electrical contacts supporting eight channels each for receive (Rx) and transmit (Tx) functions, i.e. there are eight Tx channels and eight Rx channels. Each Tx and Rx channel may propagate through one of the pluralities of optical fibers (112A and 112B), for a total of 16 optical fibers configured to propagate optical signals. The 8x8 electrical contacts are arranged as differential pairs for highspeed signal transmission. While unused pins of the Si-Fly™ connector interface (101) may be used for power and control signals, in a preferred embodiment the power and control signals may route from the foldable optical interconnect module (100) through a separate connector orAttorney Docket No. P3153-PCTelectrical cable, allowing optimal utilization of the Si-Fly™ connector's high-speed capabilities. The architecture supports multiple implementation approaches, including the option to dedicate portions of the Si-Fly™ connector's contact array for power and control functions when application requirements favor such integration. The foldable optical interconnect module (100) footprint is designed to enable dense placement of multiple interconnect modules immediately adjacent each other.

[0049] As shown in Fig. 1C, in the closed position the flexible circuit (102) extends horizontally from the Si-Fly™ connector interface (101) turns vertically and then turns back horizontally to connect to two module printed circuit board (108A and 108B), one on each side of the plane of symmetry (113). The flexible circuit (102) may include multiple conductive layers for routing high-speed differential-pair electrical signals. It is designed for controlled bending, accommodating thermal expansion mismatches and reducing stress-induced failures during operation. With continued reference to Fig. 1C, the optical carrier assemblies (103 A and 103B) may include electrooptic components (109A and 109B) which may include vertical-cavity surfaceemitting lasers (VCSELs), photodiodes, and / or a photonic integrated circuit. Each electrooptic component (109A and 109B) may have a plurality of independent optical channels. For example, a VCSEL die may have four independent emitters or a photodetector die may have four independent photodetectors and two or more VCSEL or photodetector die may be in each electrooptic component (109A and 109B). Thus, each electrooptic component (109A and 109B) can support a plurality of independent optical communication channels. Each of electrooptic components (109A and 109B) may form a group of electrooptic components that is spatially separated from the other group. Thus, electrooptic component (109A) dissipates heat into heat spreader (104A) and electrooptic component (109B) dissipated heat into heat spreader (104B). These electrooptic components enable electrical-to-optical and optical-to-electrical signal conversion. The electrooptic components (109A and 109B) may be mounted to transparent carriers (107A and 107B), respectively. Each optical carrier assembly (103A and 103B) may further include an optical block (111A and 11 IB), which route optical signals to / from electrooptic components (109A and 109B) to optical interfaces (105 A and 105B). The optical interfaces (105 A and 105B) may be configured to mate with fiber ferrules (110A and HOB), each of which support a plurality of optical fibers (112A and 112B). The optical interfaces (105A and 105B) may be configured to mate with a standardize fiber ferrule, such as, but not limited to, an optical MTAttorney Docket No. P3153-PCTferrule. Each optical carrier assembly (103 A and 103B) may also include a VCSEL driver, a transimpedance amplifier (TIA) and other interconnected electronic components (not shown in Figs. 1A-1C) mounted on two module printed circuit boards (108A and 108B). The two module printed circuit boards (108A and 108B) may each have a hole, which is covered by the two transparent substrates (107A and 107B), respectively. Portions along the outer edges of the transparent substrates (107A and 107B) may also be mounted to the module printed circuit boards (108A and 108B) enabling electrical signals to be transmitted between the module printed circuit boards (108A and 108B) and the transparent substrates (107A and 107B). Each of the transparent substrates may include electrically conductive vias (not shown in FIGS. 1A-1C), which enables electrical communication between the electrooptic components (109A and 109B) and the Si-Fly™ connector interface (101).

[0050] The heat spreaders (104A and 104B) shown in Figs. 1A-1C provide a high thermal conductivity interface between the optical carrier assemblies (103A and 103B) and an external heat dissipating surface, such as a module heat sink (160) (shown in Fig. 1C). These spreaders ensure efficient heat dissipation by providing a high thermal conductivity path between the electrooptic components and the cooling system, a relevant advantage for high-speed applications, which generally require dissipating more heat than low-speed applications.

[0001] As mentioned previously, Fig. IB corresponds to an open configuration of the foldable optical interconnect module (100). In this configuration, each optical interface (105A and 105B) is accessible for mating and unmating of a respective fiber ferrule (110A and HOB) to and from each optical carrier assembly (103A and 103B). Thus, the optically interfaces are spatially separated from each other and each optical interface (105 A and 105B) is independently connected to a group of fibers (112A and 112B), respectively. In the open configuration, the flexible circuit (102) may extend horizontally, i.e. be substantially straight and unbent, and the optical interfaces (105 A and 105B) are exposed for optical interconnection. In other words, the open configuration is used install the optical fiber connections to the foldable optical interconnect module (100). The optical carrier assembly and its internally mounted electrooptic components are aligned to provide high optical coupling efficiency between the electrooptic components (109A and 109B) and the optical fibers (112A and 112B) and this alignment is not substantially altered by bending the flexible circuit (102) into the closed position shown in Figs. 1A and 1C. In the closed position, theAttorney Docket No. P3153-PCTfiber ferrules (11 OA and 11 OB) are inaccessible and to remove the fiber ferrules (11 OA and 11 OB) the foldable optical interconnect module (100) must be placed in the open position.

[0052] The open configuration is advantageous for establishing optical connections, as the folding structure provides access that would be difficult or impossible to achieve in a fixed architecture. Once assembled, the optical connections can be implemented in different ways depending on application requirements. In some embodiments, the optical interface supports mateable and unmateable fiber connections, allowing for serviceability and reconfiguration of optical paths while maintaining the thermal and mechanical benefits of the folded structure. In other embodiments, the optical fibers may be permanently attached (pigtailed) to optimize connection reliability and minimize optical losses.

[0053] In the closed configuration as represented by Figs. 1A and 1C, the foldable optical interconnect module (100) is folded into a compact form, with the heat spreaders (104A and 104B) forming a substantially planar upper surface ready for heat sink attachment. The heat sink may be a liquid cooled cold plate, heat pipe, or a finned heat sink, or any other structure arranged to dissipate heat away from the optical interconnect module. This folded configuration is designed to maintain signal integrity for high-speed transmission through the differential contacts while simultaneously enabling high thermal conductivity between the electrooptic components and the external cooling system. The fibers exit horizontally from the module, that is perpendicular to a mating direction of the Si-Fly™ connector interface (101), and the entire assembly maintains the width of the Si-Fly™ connector footprint. This adherence to the connector footprint width is relevant to achieving next-generation interconnect density requirements. The folded architecture in this embodiment directs thermal paths vertically while maintaining lateral optical egress, preserving valuable board-edge real estate while maintaining all necessary functionality within the original connector dimensions. Alternative embodiments with vertical optical egress would direct both thermal and optical paths vertically, which would typically require a corrugated or digitated cold plate structure for heat removal.

[0054] In the closed configuration, and during operation, the electrical signal, optical signals, and thermal paths in the system follow specific directional relationships. Electrical signals from the host PCB enter through the Si-Fly™ connector interface (101) in a mating direction relative toAttorney Docket No. P3153-PCTthe board surface (first direction), then follow a U-shaped path through the flexible circuit (102) to reach the optical carrier assemblies (103 A and 103B). In operation, the flexible circuit (102) remains in this folded orientation, thus the flexible circuit (102) may be designed to maintain high signal integrity in this bent condition and need not be concerned with signal integrity in the unfolded position. Within each optical carrier assembly (103 A and 103B), the electrical signals may drive VCSELs to generate optical signals. Conversely, incoming optical signals are converted back to electrical signals by photodiodes. The optical fibers in this embodiment are routed laterally, in a direction substantially perpendicular to the mating direction of the Si-Fly™ connector interface (101) (second direction). Alternative implementations may route optical fibers vertically, parallel to the thermal path, involving thermal management solutions such as corrugated or digitated cold plates. The orientation of the optical path facilitates efficient module placement in dense configurations. Heat generated during operation is conducted through the heat spreaders (104A and 104B) to the heat sink, maintaining thermal stability. The folding mechanism allows electrooptic components to maintain high thermal conductivity contact (including the possibility of a thin thermal interface material layer) with the heat spreaders. In particular, the thermal path extends in a third direction, which may be opposite the mating direction of the Si-Fly™ connector interface (101) and is optimized for heat transfer to the external cooling system. This ensures optimal heat dissipation during operation, addressing the thermal challenges of generating and receiving high-speed optic signals.

[0055] This high thermal conductivity is advantageous given the mix of heat-generating and temperature-sensitive components in the optical carrier assemblies (103A and 103B). While the VCSEL driver integrated circuits generate most of the thermal load during operation, the VCSELs themselves degrade at high temperatures and often only maintain optimal performance over a limited temperature range. The folded architecture enables both the semiconductor driver circuits, such as the VCSEL driver, and electrooptic components, such as the VCSELs, to share the same high thermal conductivity path through the heat spreaders (104A and 104B). Top surfaces of the heat spreaders (104A and 104B) may form a flat common thermal interface (114) configured to dissipate heat to the module heat sink (160). This arrangement ensures that heat from the drivers is effectively channeled away while maintaining stable thermal conditions for the temperaturesensitive electrooptic components.Attorney Docket No. P3153-PCT

[0056] Alternative thermal management configurations are also possible. For example, a common liquid cooled plate may extend across both the processing chip and all the foldable optical interconnect modules (100). As a further alternative all the optical interconnect modules may have a common cooling system independent from that of the processor. Such independent cooling systems enable the optical interconnect modules and the processing unit to be maintained at different operating temperature ranges. For example, because electrooptic components such as VCSELs and other laser light sources degrade at elevated temperatures and maintain optimal performance only within a limited temperature range, the cooling system for the optical interconnect modules may be configured to maintain the optical interconnect modules at a first, lower operating temperature range, while the processing unit, which can tolerate higher operating temperatures, may be maintained at a second, higher operating temperature range by its independent cooling system. As yet an another alternative two adjacent row of optical interconnect modules can have a common “L’ shaped heat sink. In this embodiment two “L” shaped heat sinks would be required to dissipate heat from the four rows of modules that surround the processor. Whether using a common or separated heat dissipating surface or heat sink (e.g. a cold plate) approach, the folded architecture maintains its advantages in interconnect density and thermal efficiency.

[0057] The thermal design of the foldable optical interconnect module (100) provides several advantages. By allowing the electrooptic components in the optical carrier assemblies (103 A and 103B) to sit in direct thermal contact (i.e., mechanical contact or via a thin thermal interface material) on the heat spreaders (104 A and 104B) during assembly and operation, the design achieves an ideal thermal path. This direct thermal contact would not be possible with a nonfolding design where the optical carrier assembly was mounted directly on top of the PCB, as the PCB could introduce additional thermal resistance. The folding architecture thus enables superior thermal performance while maintaining the compact footprint defined by the Si-Fly™ connector interface (101).

[0058] The flexible circuit (102) serves multiple purposes beyond simply routing electrical signals. The flexible circuit portion includes multiple conductive layers for signal routing, controlled impedance structures for maintaining signal integrity through the fold, and mechanical features to accommodate coefficient of thermal expansion (CTE) mismatches between differentAttorney Docket No. P3153-PCTcomponents, reducing stress on solder joints and other interconnections during thermal cycling. Additionally, the flexible circuit (102) can be implemented as either single-layer or multilayer circuits allowing optimization of signal routing density versus manufacturing complexity.

[0059] An additional advantage of the foldable embodiment is that optical fiber routing in the folded configuration may facilitate the implementation of mateable and unmateable fiber connections through standardized optical interfaces such as a MT connector interface oriented perpendicular to a mating direction of the Si-Fly™ connector interface (101). This ability to make and break optical connections provides significant operational advantages, allowing individual optical connections to be established or disconnected for system maintenance, troubleshooting, or reconfiguration. Such serviceability represents an improvement over fixed fiber attachment solutions that require permanent fiber termination.

[0060] Fig. 2A shows an exemplary modular optical interconnect module (200) according to a second embodiment of the present disclosure. Figs. 2B-2C represent two and three-dimensional cross sections of the embodiment of Fig. 2A, respectively. Fig. 2C shows a rotated view of the optical interconnect module for ease of illustration, with the device oriented on its side to better display the internal components. In actual operation, the device is rotated 90 degrees from this view, such that sub-modules (201) are mounted perpendicular to the host system substrate, and the optical fibers (205) exit vertically upward. Figs. 2A-2B provide additional views that further illustrate the internal components and their arrangement within the assembly. The modular optical interconnect module (200) may be mated to an underlying substrate (not shown in Figs. 2A-2C) by placing the module above the substrate and moving the module towards the substrate in a mating direction as shown in Fig. 2A.

[0061] With continued reference to Figs. 2A-2C, modular optical interconnect module (200) comprises multiple stackable sub-modules (201), a common thermal interface (202), printed circuit board (PCB) assemblies (203), and a Si-Fly™ connector interface (206). Unlike the embodiment described above relative to Figs. 1A-1C, in this embodiment optical fibers (205) are oriented vertically, parallel with the mating direction of the Si-Fly™ connector interface (206). The common thermal interface (202) spans across the top of the stacked sub-modules (201) and provides a continuous heat dissipation path across all sub-modules (201) for efficient system-levelAttorney Docket No. P3153-PCTthermal management. This embodiment emphasizes scalability for high-channel-count systems. Each sub-module (201) includes PCB assemblies (203), optical elements (such as VCSEL arrays, photodiodes, and / or photonic integrated circuits), and an optical interconnection. Sub-modules (201) may be tested independently prior to assembly, reducing the risk of defects in high-density configurations.

[0062] As disclosed above, the common thermal interface (202) spans the top of the stacked sub-modules (201) and provides a continuous, low thermal impedance heat dissipation path. It is compatible with liquid cooling systems and ensures efficient system-level thermal management through more efficient heat transfer as compared to air cooling. The common thermal interface (202) is formed by a stack of sub-module heat spreaders (210) placed adjacent each other to form a flat continuous surface. Each sub-module (201) may have a heat spreader (210) which dissipates heat generated by electrical and electrooptic elements in the sub-module, providing initial thermal management at the sub-module level. Heat generated by the electrooptic and electronic elements flows through the sub-module heat spreader (210) to the common thermal interface (202). An external heat sink may be mechanically compressed against the common thermal interface (202) to create a flat, smooth thermal interface, enabling heat removal through the external heat sink. The external heat sink may take many forms, such as but not limited to a heat pipe, cold plate (i.e. a plate having passageways with flowing liquid coolant), or forced air cooling system. As shown in more detail below, the external heat sink has openings to allow egress of the optical fibers (205) through the external heat sink.

[0063] With further reference to Figs. 2A-2C, the PCB assemblies (203) manage high-speed signal routing and electrical grounding. Each PCB assembly (203) incorporates dedicated ground planes arranged between signal layers to provide controlled impedance environments and minimize crosstalk between adjacent signal traces. The ground planes extend through the stack of PCB assemblies (203) and connect to ground contact elements within the Si-Fly™ connector interface (206). In particular, the interlocking plates of the Si-Fly™ connector interface (206) that define the signal pair cavities also serve as ground shields, with the ground planes in the PCB assemblies (203) making direct electrical contact to these shield structures. This continuous ground architecture, extending from the Si-Fly™ connector interface (206) through the entire module stack, allows maintaining signal integrity at high data rates.Attorney Docket No. P3153-PCT

[0064] Fig. 2D shows a cross-sectional view of the same embodiment as in Fig. 2C and illustrates the ground plane arrangement. Fig. 2D shows radio frequency (RF) ground planes (250) extending from the Si-Fly™ connector interface (206) throughout the integrated PCB assemblies (203). Distribution paths for power, control signals, and their associated low-speed return paths (252) are provided by pins (207) that extend between the PCB assemblies (203) in a direction orthogonal to the RF ground planes (250). The power, control signals, and their associated low-speed return paths may originate in a power and control printed circuit board (209), which is mounted adjacent to the integrated PCB assemblies (203). Holes in the RF ground planes (250) (not visible in Fig. 2D) allow the power and control paths (252) to extend through the RF ground planes (250).

[0065] Fig. 2E shows a perspective view of an individual sub-module (201) according to an embodiment of the present disclosure. High speed data signals may enter and exit the sub-module (201) along a bottom edge (254), which is adjacent to the Si-Fly™ connector interface (206) (not shown in Fig. 2E) in an assembled modular optical interconnect module (200). Electrooptic components (not visible in Fig. 2E) convert optical signals into electrical signals and / or convert electrical signals into optical signals. A right-angle optical interconnect (204) couples the optical signals between the electrooptic components and the optical fibers (205). Power, control signal, and returns make electrical contact with the sub-module (201) through pin socket (208), which may be arranged along two opposing edges of the sub-module (201). The pin socket (208) are electrically conductive so that the power and control signals are in electrical connection with the sub-module (201) and allow conductive pins (see Fig. 2F) to pass through the sub-module (201) so that the power and control signals can reach other sub-module (201) in the modular optical interconnect module (200). The sub-module heat spreader (210) forms a top side of the submodule (201) opposed to the bottom side where the electrical data signals enter and exit the submodule (201). The optical fibers (205) extend off the top side of the sub-module (201).

[0066] Fig. 2F shows an electrical arrangement for the power, control signals, and their return paths according to an embodiment of the present disclosure. Conductive pins (207) may form two rows and may extend from two pin headers (260). The pin headers (260) may be mounted on opposing sides of the power and control printed circuit board (209). The power and control printedAttorney Docket No. P3153-PCTcircuit board (209) may be displaced from and oriented parallel to the sub-modules (201) (see Fig.2D).

[0067] Returning to Figs. 2A-2D, the optical fiber routing structures comprise dedicated pathways and support elements integrated into each sub-module (201) that guide and secure the optical fibers (205) in their vertical orientation, enabling vertical fiber egress from each submodule (201), eliminating interference between adjacent modules. This vertical arrangement facilitates tight packing of modular optical interconnect modules (200) in high-bandwidth applications. The modular optical interconnect module (200) is assembled by stacking submodules (201) along a horizontal direction. Horizontally oriented conductive pins (207) extend through pin sockets (208) distributing power and control signals across the stack of sub-modules (201), ensuring all sub-modules have access to the power and control signals. Pin sockets (208) may be preferably implemented as SIP (Single In-Line Package) connectors, although in some embodiments button connectors may also be envisaged. The pins (207) are routed to a power and control PCB (209) that manages the power and control of the entire interconnect module. This power and control PCB may interconnect to a larger system through a connector or ribbon cable as described in more detail below. In operation, high-speed electrical signals enter / exit through the Si-Fly™ connector interface (206) at its base and are distributed to the integrated PCB assemblies (203) in each sub-module (201). These signals may drive the electrooptic elements, generating vertically directed optical signals that exit through the fiber routing structures. Similarly, received optical signals may be converted to electrical signals in the electrooptic elements and directed out through the Si-Fly™ connector interface (206). Heat is managed collectively through the common thermal interface (202), which is compatible with external cooling solutions. The common thermal interface (202) ensures uniform cooling across the stacked configuration. According to the teachings of the present disclosure, such a modular approach supports configurations ranging from 16 to 64 optical data channels by adding or removing submodules (201) from the Si-Fly™ connector interface (206). An 8x8 Si-Fly™ connector interface can have up to 64 differential pair signals, so the modular optical interconnect modules (200) may support up to 64 optical data channels. An advantage of this architecture is that each of the submodules (201) may tested and its operation verified prior to placing the sub-module in the stack, improving yield and reducing manufacturing risk.Attorney Docket No. P3153-PCT

[0068] Signal routing within each sub-module (201) requires careful consideration of density constraints. The electrooptic components, including VCSELs and photodiodes, are arranged to optimize both electrical and thermal performance. Thermal performance may be optimized by the shape and arrangement of the sub-module heat spreader (210) shown in Figs. 2G and 2H. Fig. 2G shows a perspective view of an individual sub-module heat spreader (210). The sub-module heat spreader (210) may have a “T” like shape with an extended arm (264) topped by a cap (266) having a cut out (268) to allow for fiber egress. A top surface of the cap (266) may form part of the common thermal interface (202). A thermal interface pad (270) may be placed at an end of the extended arm (264) opposite the cap (266). This region of the sub-module heat spreader (210) may be situated directly beneath the electrooptic components when the sub-module heat spreader (210) is integrated into a sub-module (201). The thermal interface pad (270) may facilitate heat transfer from the electrooptic components into the extended arm (264) of the sub-module heat spreader (210). The waste heat may then spread to the cap (266) and be dissipated out from the common thermal interface (202).

[0069] Fig. 2H shows a perspective view of a modular optical interconnect module (200) according to an embodiment of the present disclosure. This figure is similar to Fig. 2A, but from a different perspective. Fig. 2H illustrates placement of the sub-module heat spreader (210) on a back side of the PCB assembly (203). This placement enables the sub-module heat spreader (210) to effectively dissipate heat from the electrooptic components to the common thermal interface (202).

[0070] Thermal management in the modular design follows a hierarchical approach. At the sub-module level, the sub-module heat spreaders (210) provide in a high thermal conductivity path for the electrooptic components. The submodule heat spreaders (210) stacked together adjacent each other provide the common thermal interface (202) for all sub-modules (201). Heat can be removed from the common thermal interface (202) using various approaches, including but not limited to, a heat pipe, a solid copper or aluminum slug, a liquid-cooled plate, or forced air convection with a finned heat sink. The chosen heat removal method depends on thermal requirements of the modular optical interconnect module (200). This thermal architecture ensures efficient heat transfer while maintaining the mechanical integrity of the stacked configuration. The thermal management system employs a hierarchical approach through a unified thermal interfaceAttorney Docket No. P3153-PCTthat comprises local heat spreading elements within each sub-module, coupled to a common thermal structure for heat removal. This arrangement operates in concert with electrical signal routing elements that include both interconnect elements for power / control distribution and specific signal integrity structures designed to maintain high-speed signal performance. The entire system maintains the compact system footprint of the Si-Fly™ connector interface (206).

[0071] The modular design enables efficient manufacturing and assembly through its submodule-based architecture. Each sub-module (201) may be designed to handle, for example, 16 channels, with each sub-module (201) electrically connected to two rows of differential pair contacts in the in the Si-Fly™ connector interface (206). This standardized approach allows for systematic scaling of channel capacity by adding additional sub-modules to the stack. The design can accommodate various configurations ranging from 8 channels using a single sub-module (201) connected to a single row of differential pair contacts, up to 64 channels using eight sub-modules with each sub-module connected to two rows of differential pair contacts. Each of these configurations, and any intermediate configuration, can maintain the same Si-Fly™ connector interface.

[0072] The stacked sub-modules may be assembled into a rigid structure held together by mechanical compression, such as through bolts, clamps, or other compression mechanisms. This compressive assembly approach serves multiple purposes: it ensures reliable thermal contact between the sub-modules (201) and the common thermal interface (202), maintains consistent electrical connections through the sub-modules (201), and enables disassembly for maintenance or upgrades. The compression mechanisms are designed to apply uniform pressure across the stack, optimizing both thermal and electrical contact while allowing the stack to be disassembled when needed without damaging the individual sub-modules. This ability to disassemble the stack is advantageous for servicing, replacing, or upgrading individual sub-modules, as well as for accessing the optical connector interfaces when implementing mateable / unmateable fiber connections. The compression may be achieved through corner bolts that extend through alignment features in each sub-module (201), through external clamping mechanisms that apply pressure to the top and bottom of the stack, or through a combination of both approaches to ensure uniform compression across the entire assembly.Attorney Docket No. P3153-PCT

[0073] The vertical optical fiber egress architecture provides distinct advantages for high-density applications. Unlike horizontal fiber routing schemes which can create routing conflicts with other elements on the host PCB, the vertical approach enables seamless side-by-side placement of multiple modular optical interconnect modules (200) and eliminates potential interference between adjacent electrical components on the host PCB. This is particularly beneficial in applications where interconnect modules must be densely packed around the periphery of processing units such as Al chips.

[0074] The vertical fiber egress architecture may employ a pigtailed fiber configuration, where optical fibers are permanently integrated into each sub-module (201). These permanently integrated optical fibers (205) are configured specifically for vertical egress from the modular optical interconnect module (200). The permanent integration ensures that the vertical fiber egress is reliably maintained even in dense configurations where multiple modular optical interconnect modules (200) are placed laterally adjacent to each other.

[0075] While the vertical fiber egress architecture may employ a pigtailed fiber configuration as described above, in an alternative embodiment a mateable / unmateable fiber connection is provided to each sub-module (201). In one such implementation, the thermal core may include mirrored optical engines on each sub-module (201) with an optical connector interface (such as a RVCON™ interface manufactured by Samtec Inc.) arranged in a two rows of optical fiber or a wide single row of optical fibers. These configurations may physically correspond to the array of cavities in the Si-Fly™ connector housing.

[0076] The configuration depicted in Figs. 2A-2H enables each sub-module (201) to be preassembled and tested with its optical connections intact, maintaining fixed optical alignment within each sub-module. The pigtailed configuration, combined with vertical fiber egress, maintains the compact footprint defined by the Si-Fly™ connector interface (206). After pre-testing, the submodules are stacked to form the complete modular optical interconnect module (200), with the pigtailed fibers from each sub-module maintaining their vertical egress in the stacked configuration. The permanent integration of optical fibers enables improved use of the available space in the stack while maintaining the compact footprint defined by the Si-Fly™ connector interface (206). The fixed fiber integration also provides advantages in terms of optical alignmentAttorney Docket No. P3153-PCTstability and simplified initial assembly, as each sub-module can be pre-assembled and tested with its optical connections intact. This approach is particularly well-suited for applications where the emphasis is on maximum density and reliable long-term deployment rather than reconfiguration of optical connections.

[0077] The modular design's emphasis on independent testing and verification of sub-modules before final assembly represents a significant manufacturing advantage. Each sub-module (201) can be independently tested prior to system integration. This approach reduces yield risks associated with high-channel-count configurations by allowing defect identification and replacement at the sub-module level rather than requiring replacement of entire high-channel-count assemblies. The system is inherently configurable for different channel counts simply by varying the number of sub-modules used in the final assembly.

[0078] While the main embodiment employs rigid printed circuit boards to ensure optimal electrical performance at high data rates, the architecture can potentially accommodate alternative implementations including multilayer flex circuits or a rigid-flex combination. Each implementation approach presents distinct trade-offs between signal integrity, mechanical flexibility, and thermal management that should be evaluated based on specific application requirements and performance targets.

[0079] Features that are common to the foldable and modular embodiments of the optical interconnect module and arrangement according to the present disclosure will now be discussed.

[0080] Both the foldable and modular embodiments share several architectural elements that address fundamental challenges in high-density optical interconnect design. Common to both approaches is the Si-Fly™ connector interface, which provides a high-performance electrical connection to a substrate, such as a host PCB or IC package substrate, while enabling dense placement of multiple optical interconnect modules adjacent to each other. In both implementations, the Si-Fly™ connector interface serves as the foundation for routing high-speed signals. Power and control signals may also be routed through the Si-Fly™ connector interface or alternatively may be routed to the optical interconnect module by an electrical cable or another connector.Attorney Docket No. P3153-PCT

[0081] Additionally, the thermal management strategy in both embodiments reflects a common philosophy of providing direct thermal paths from the electrooptic components to the cooling system. While the specific implementations differ both architectures prioritize thermal efficiency by establishing direct thermal conduction pathways between heat-generating components and the cooling solution, minimizing the number of thermal interfaces and having high thermal conductivity material between heat-generating components and the cooling solution. In particular, both architectures employ a unified thermal interface that provides consistent and low impedance thermal coupling between the electrooptic components and the external cooling system. This is particularly advantageous in artificial intelligence applications where multiple interconnect modules may be arranged around a central processor.

[0082] Signal routing in both embodiments demonstrates innovative approaches through a signal distribution structure that manages the three fundamental requirements of optical interconnect modules or arrangements: electrical pathways, optical fiber pathways, and thermal conduction pathways. Each design creates a unique solution for harmonizing these requirements while maintaining signal integrity and mechanical stability. The foldable embodiment achieves this through its flex circuit and folded architecture, while the modular embodiment utilizes a stacking approach. Despite their different implementations, both designs succeed in maintaining the compact footprint defined by the Si-Fly™ connector while enabling high-density placement of multiple interconnect modules.

[0083] The signal routing structures in these dense arrangements employ, for example, highspeed differential signal pairs maintained within controlled impedance environments. For example, each speed differential signal pair may be situated within a cavity surrounded by a ground shield. Adjacent modules are configured to share thermal and mechanical interfaces while maintaining optical isolation, with fiber routing structures directing optical fibers either perpendicular to the plane of the processing unit or away from the processing unit parallel to the plane of the processing unit. The modules may be specifically arranged around the periphery of the processing unit to optimize both signal routing and thermal management.

[0084] Manufacturing considerations are addressed in both embodiments through designs that facilitate assembly and testing. The foldable architecture provides access for optical alignment andAttorney Docket No. P3153-PCTfiber attachment before folding into its final form, while the modular approach enables independent testing of sub-modules before final assembly. These features contribute to improved manufacturing yield and reliability in high-volume production scenarios.

[0085] Fig. 3 shows an exemplary optical interconnect system (300) in accordance with an embodiment of the present disclosure. Optical interconnect system (300) comprises a host PCB (301), a Si-Fly™ connector base (302) mounted on host PCB (301) and an auxiliary cable (303) carrying power and control signals from the host PCB (301) to the optical interconnect module (310). The optical interconnect module (310) may comprise a Si-Fly™ connector interface (304) and an optical engine (312) situated on top of the Si-Fly™ connector interface (304). The optical engine (312) may take either the folded architecture form described above relative to Figs. 1 A-1C or the stacked architecture form described above relative to Figs. 2A-2H. Note that the vertical fiber egress of the stacked architecture is shown in Fig. 3, but in the folded architecture the optical fibers (112) would be oriented horizontally. In the embodiment shown in Fig. 3, the host PCB (301) is connected to optical interconnect module (310) using a combination of the Si-Fly™ connector system and the auxiliary cable (303). The Si-Fly™ connector system may comprise a Si-Fly™ connector base (302) and a Si-Fly™ connector interface (304). The Si-Fly™ connector base (302) may be soldered to the host PCB (301). In an embodiment, the auxiliary cable (303) may be permanently attached to the optical interconnect module (310). In another embodiment the auxiliary cable (303) may be mateable / unmateable from the optical interconnect module (310), the host PCB (301) or both the optical interconnect module and host PCB. According to the teachings of present disclosure, optical interconnect module (310) may be implemented using either the foldable optical interconnect module (100) shown in Figs. 1A-1C or the modular optical interconnect module (200) shown in Figs. 2A-2H.

[0086] The separation of high-speed signals and power / control signals shown in Fig. 3 provides several technical advantages. The Si-Fly™ connector's high-speed differential pair capacity can be fully utilized for data transmission, as the connector's array of contacts supports multiple layers of high-speed channels for both receive (Rx) and transmit (Tx) functions. By routing power and control signals through the auxiliary cable (303), the design maintains optimal use of the Si-Fly™ connector's high-density signal capabilities while ensuring reliable power and control signal distribution. This arrangement is particularly advantageous in high-channel-countAttorney Docket No. P3153-PCTimplementations where the full capacity of the Si-Fly™ connector interface is needed for highspeed differential pairs.

[0087] The separation of high-speed signals and power / control signals into distinct pathways reflects an optimization of connector resource utilization. The high-density differential pair capacity of the Si-Fly™ connector base (302) is preserved for high-speed signal transmission, while the auxiliary power and control cable (303) provides a dedicated path for power distribution and control signaling. This architecture maintains signal integrity for high-speed transmission while ensuring reliable power delivery and control functionality.

[0088] In alternative embodiments, power and control signals may be routed to the optical interconnect module (310) differently than the approach depicted in Fig. 3. In a first approach, certain cavities in the Si-Fly™ connector interface are dedicated to power and control signals, with a first portion of the cavities containing high-speed differential signal contacts and a second portion of the cavities containing power and control signal contacts. In a second approach, high-speed signals and power signals are routed through the Si-Fly™ connector interface, while control signals are transmitted wirelessly using RF protocols like Bluetooth / WiFi. In a third approach, control signals are implemented using an optical protocol sent to the optical interconnect module (310) via the optical fibers (112). In a fourth approach, shown in more detail in Figs. 5A-5E, an auxiliary connector may be positioned near the Si-Fly™ connector interface (304). The adjacent low-speed connector may mate simultaneously with the Si-Fly™ connector interface, utilizing a dual-connector arrangement that preserves the module's width while enabling separate optimization of high-speed and low-speed signal path. One or more microprocessor s) within the optical interconnect module (310) may interpret the control signals and direct the optical interconnect module (310) to operate as directed by the control signals. All of these approaches maintain the small footprint for the optical interconnect module (310) while still providing all necessary connections.

[0089] In accordance with the teachings of the present disclosure, multiple optical interconnect modules may share a common heat dissipating surface and may be electrically connected with the same processing unit. In order to further clarify this, reference is made to Figs. 4A-4B illustrating such teachings in an exemplary manner. Fig. 4A shows a schematic cross-sectional view of anAttorney Docket No. P3153-PCToptical system comprising multiple optical interconnect modules (400) arranged around a periphery of and connected to processing unit (180). The processing unit (180) and the Si-Fly™ connector bases (302) may both be soldered to an IC package substrate (184). The optical interconnect modules (400) may be mated to the Si-Fly™ connector bases (302). The optical interconnect modules (400) may contact a module heat sink (160). Single module heat sink (160) may contact both optical interconnect modules (400) or there may be separate module heat sinks for modules on opposing sides of the processing unit (180). While the optical interconnect modules (400) maintain individually serviceable optical connections, they may share a common heat dissipating surface as exemplarily represented by heat sink (160). A stiffener (182) may surround the processing unit (180) and provide additional mechanical rigidity to the IC package substrate (184).

[0090] While Figs. 4A illustrates an implementation with lateral optic fiber (112) egress, alternative embodiments may include a processing unit with optical interconnect modules having vertical fiber egress, providing additional flexibility in system design. Fig. 4B shows an embodiment with vertical optical fiber egress. Fig. 4B has many common features with Fig. 4A and for brevity only differences between Figs. 4A and 4B will be described. A major difference between Figs. 4A and 4B is that the optical fibers (112) have a vertical egress from the optical interconnect modules (400). As a result, the module heat sink (160) has openings (162) so as not to block the optical fibers (112) from exiting or entering the optical interconnect module (400).

[0091] Although only two optical interconnect modules (400) are shown in Figs. 4A-4B, embodiments including more than two optical interconnect modules may be envisaged surrounding a processing unit (180) or more generally an IC die. Examples of such embodiments are shown in Fig. 5A-5E, 6A, and 6B.

[0092] Fig. 5A is a simplified perspective view of a high-density optical interconnect arrangement, also referred to as a high-density interconnect module arrangement, in which multiple interconnect modules (502, 503) are co-packaged with an IC die (504) on an IC die package substrate (506). The high-density interconnect modules (502, 503) are distributed along the four sides of the IC die (504) (e.g., an ASIC, GPU or CPU) on the IC package substrate (506) in a rectangular arrangement. The IC package substrate (506) may be mounted to a host PCB (508).Attorney Docket No. P3153-PCTThe IC package substrate (506) may have dimensions of 105 mm x 105 mm, although both smaller, for example, 95 mm x 95 mm, and larger, for example, 120 mm x 120 mm, and other sizes of the IC package substrate are possible.

[0093] Each interconnect module (502, 503) may mate via a Si-Fly™ connector interface (521) or similar high-speed interface, with cables extending outward for optical or electrical interconnections. The interconnect modules (502, 503) may be deployed in a rectangular pattern around the IC (504) die with high-speed signals and any auxiliary cables coming out from each interconnect module (502, 503) while maintaining a compact form factor on the host PCB (508). A mix of optical interconnect modules (502) and electrical interconnect modules (503) may be present as shown in Fig. 5 A or only a single type of interconnect module may be used. As shown in the figures, particularly Fig. 5A, the optical cables (512) may extend primarily from one side of each optical interconnect module (502), which creates an organized cable routing arrangement.

[0094] As shown in the figures, particularly Fig. 5A, both optical and electrical cables extend primarily from one side of their respective interconnect modules, which creates an organized cable routing arrangement. Each optical interconnect module (502) typically connects to significantly fewer cables than a comparable electrical interconnect module (503), since each optical cable, such as an optical ribbon cable, has multiple optical fibers, whereas each electrical cable can only support a single signal path. Thus, each electrical interconnect module (503) may connect to as many as 64 twinax electrical cables whereas only 8 optical cables, with each optical cable having 8 optical fibers, would be needed for an optical interconnect module (502) having the same number of data channels. This reduced cable count represents an advantage of optical interconnect modules, as it simplifies cable management in high-density computing environments.

[0095] In some applications, some interconnect modules may be electrical interconnect modules (503) in which high-speed electrical signals are transmitted via electrical cables and some of the interconnect modules may be optical interconnect modules (502) in which high-speed optical signals are transmitted over an optical cable (512). The optical cable may be in the form of a ribbon cable having a plurality of optical fibers distributed in a row. Optical interconnect modules (502) convert high-speed electrical signals coming from the IC die (504) into high-speed optical signals transmitted down the optical cable (512) and / or convert high-speed optical signals comingAttorney Docket No. P3153-PCTfrom the optical cable into high-speed electrical signals transmitted through the IC package substrate (506) to the IC die (504). Also shown in Fig. 5A is an optional stiffener (520) to reduce warping of the IC package substrate (506). The stiffener (520) appears as a square-shaped frame that surrounds the IC die (504) and runs between the rows of interconnect modules, providing structural support to the package.

[0096] While Fig. 5A shows the general arrangement of interconnect modules surrounding an IC die, the specific routing of power and low-speed control signals to each module can be implemented in different ways. Figs. 5B-5E, described below, illustrate three exemplary approaches for supplying these non-high-speed signals to the same types of interconnect modules (both electrical and optical) shown in Fig. 5A.

[0097] It should be noted that electrical interconnect modules (503) may be implemented as passive components without requiring power or control signals in some embodiments, while in other embodiments they may incorporate active components that do require such signals. In contrast, optical interconnect modules typically require both power and control signals for the optical-electrical conversion operations. The following examples apply primarily to optical interconnect modules and to any electrical interconnect modules that incorporate active components requiring power or control signals.

[0098] In particular, Figs. 5B-5E show, by way of example, three alternative approaches for routing power and low-speed control signals to an interconnect module (e.g., module 310 in Fig.3), either in addition to or separate from the high-speed differential signals carried by a Si-Fly™ connector base (510). As previously discussed in the present specification, these alternatives allow design flexibility in delivering power and control functions to the same module that handles highspeed data interconnects.

[0099] It should be noted that whereas in earlier embodiments (e.g., as shown in Fig. 3) the Si-Fly™ connector base (510) was mounted to the host PCB (508), in the arrangements shown in Figs. 5A-5D the Si-Fly™ connector base (510) is mounted directly on the IC package substrate (506) in a manner similar to that shown in Figs. 4A and 4B. This "co-packaged" approach brings the interconnect modules (502, 503) much closer to the IC die (504), and may have, in someAttorney Docket No. P3153-PCTembodiments, several advantages, such as: reducing signal path lengths, improving signal integrity, and / or enabling higher data rates while reducing power consumption.

[0100] Fig. 5B shows a perspective view of an electronic assembly wherein all signals — both high-speed and non-high-speed (power / control) — are routed through the same Si-Fly™ connector base (510). The shape and configuration of the non-high-power contacts may be different than the differential pair contacts that support the high-speed data signals.

[0101] The IC package substrate (506) lies under the Si-Fly™ connector base (510) and mates with the Si-Fly™ connect interface (521) of the optical interconnect module (502). The optical interconnect module (502) transmits both high-speed electrical signals as differential pairs and auxiliary (power, low-speed control) signals through the single connector interface between them. High-speed optical signals can be transmitted through the optical cables (512) emerging from the module. Two ribbon cables are shown associated with each module in Fig. 5B, with each ribbon cable containing multiple optical fibers arranged in parallel rows, but other types of optical cables can be used. Also shown in Fig. 5B is a stiffener (520), which extends between the adjacent rows of interconnect modules.

[0102] This "single-connector" arrangement can reduce component count and simplify the mechanical interface, although it may allocate some of the high-speed contact array for non-high-speed signals. As previously noted in the specification, such an approach is particularly attractive if the total number of high-speed pairs is moderate or if reassigning unused pins for power / control is acceptable.

[0103] Fig. 5C shows a similar assembly in which the high-speed signals remain in the Si-Fly™ connector base (510), but power and control signals are instead routed through a separate auxiliary connector (516) on the side of the optical interconnect module (502) facing away from the IC die (504). This arrangement allows the auxiliary connector (516) to make direct contact with the host PCB (508) through a different set of pins or pads (518) than used in the Si-Fly™ connector base (510). As shown in Fig. 5C, the auxiliary connector (516) appears as a small rectangular component at the top edge of the interconnect module, with corresponding contact pads (518) visible on the surface below. The auxiliary connector (516) preserves the high-speedAttorney Docket No. P3153-PCTcapacity of the main Si-Fly™ interface for data signals only, while ensuring that the non-high-speed lines reach the optical interconnect module via a more specialized or simpler connector.

[0104] As previously noted in the present specification, partitioning out the low-speed or power lines can help maintain signal integrity on the dense differential pairs in the primary, differential pair connector.

[0105] Fig. 5D provides an example wherein the optical interconnect module includes a dedicated ribbon or flex auxiliary electrical cable (514) that exits the module housing and connects to a connection point on the IC package substrate (506) or host PCB (508) for power / control distribution. As shown in Fig. 5D, the auxiliary cable (514) may extend from near the top of the optical interconnect module (502) and routes across the surface of the host PCB (508), providing a third alternative connection method.

[0106] In this "auxiliary-cable" configuration, the module's high-speed signals still pass through the Si -Fly™ connector, but a flexible electrical cable (514) is used for lower-speed signals and power rails. The IC package substrate or host PCB would have a mating receptacle, terminal block, or solder pads to receive this cable.

[0107] As previously noted in the present specification, having the low-speed / power lines separated in this manner can improve mechanical flexibility and ease of cable routing, particularly if the placement of support circuitry or power rails on the IC package substrate is not directly adjacent to the primary differential signal pair connector region.

[0108] It will be appreciated that each of these three power / control routing solutions (Figs.5B-5D) can be applied to either the foldable interconnect embodiment (Figs. 1A-1C) or the modular, stackable embodiment (Figs. 2A-2H), regardless of whether the module is an electrical or optical interconnect module. In all cases, the high-speed paths are carried by the Si-Fly™ connector base (510) and the Si-Fly™ connector interface (521), and the auxiliary signals — power and / or low-speed housekeeping lines — may be handled through (a) the same Si-Fly™ connector, (b) an auxiliary connector adjacent to it, or (c) a separate ribbon / flex cable that plugs into the IC package substrate or host PCB.Attorney Docket No. P3153-PCT

[0109] For clarity, the IC package substrate and host PCB are only partially shown in FIGS.5B-5D. One of ordinary skill will recognize that the IC package substrate is physically below the Si-Fly™ connector in these illustrations, and that any additional connectors, headers, cable receptacles, or test points for low-speed signals can be located at any convenient placement on the IC package substrate or host PCB.

[0110] The assemblies and signal paths depicted in FIGS. 5A-5D are exemplary only. Other variations, such as wireless control interfaces or further partitioning of power rails, are possible without departing from the scope of the present disclosure.

[0111] Fig. 5E shows a zoomed-in top view of the interconnect module arrangement of Fig.5A where one of the optical interconnect modules adjacent to the stiffener (520) is removed to show further details of electrical contacts (550) of the Si-Fly™ connector base (510). In this zoomed view, the electrical contacts (550) are clearly visible as an array of connection points on the surface of the connector, showing the high-density nature of the interface. The electrical contacts (550) may be arranged in an array of eight-by-eight differential pair contacts as shown in Fig. 5E, although other electrical contact arrangements may be used. The density and arrangement of these contacts illustrates the connector’s capability to handle multiple high-speed differential signal pairs and other connections in a compact form factor. The relative scale of these contacts compared to the overall module and stiffener provides insight into the miniaturization achieved in this high-density interconnect system.

[0112] The auxiliary connector (516) for low-speed control signals and / or power is visible adjacent to the Si-Fly™ connector base (510). The auxiliary connector (516) may have a row of electrical contacts (552) that are configured to mate with the interconnect module when the interconnect module is mated with the Si-Fly™ connector base (510). In the embodiment shown in Fig. 5E the auxiliary connector (516) makes direct electrical contact with the underlying host PCB so that the power and control signals do not need to be on the IC die package substrate (506).

[0113] An advantage of any of the previously described embodiments of an optical interconnect module is that its electrical interface may be identical to that of an electrical cable connector. This advantage is clearly shown in Fig. 5A, which shows a mix of optical interconnect modules (502) and electrical interconnect modules (503) surrounding an IC die. It should beAttorney Docket No. P3153-PCTappreciated as the needs of the surround operating environment change; optical interconnect modules can be swapped with electrical interconnect modules and vice versa. This feature enables high-bandwidth optical signal transmission while maintaining mechanical and electrical compatibility with the existing Si-Fly™ connector base (510). The optical interconnect modules (502) mate with the Si-Fly™ connector base (510) in a similar mechanical fashion to previous cable connectors but perform the additional function of converting between electrical and optical signals, with optical fibers carrying signals rather than electrical cables. This approach maintains the proven mechanical and electrical interconnection architecture while enabling the higher bandwidth and longer transmission distances inherent to optical communications.

[0114] Fig. 6 shows a perspective view of cooling system for a plurality of optical interconnect modules according to an embodiment of the present disclosure. Fig. 7 is an exploded view of Fig.6 showing a cooling system for a plurality of optical interconnect modules according to an embodiment of the present disclosure. Referring first to Fig. 7, which shows an arrangement of optical interconnect modules (502) surrounding an IC die (504) mounted on a host PCB (508). The optical interconnect modules (502) are co-packaged with the IC die (504) so that electrical signals transmitted between them do not need to pass through the host PCB (508). This portion of Fig. 7 is similar to Fig. 5A except that all positions around the IC die (504) are occupied by optical interconnect modules (502) rather than the mix of optical interconnect modules and electrical interconnect modules depicted in Fig. 5A. The depicted optical interconnect modules (502) have a separate auxiliary connector as previously described relative to Fig.5C, but any of the other previously disclosed arrangements for supplying power and control signals to the optical interconnect module may be used. The optical interconnect modules (502) are arranged in four rows (522A-522D) of optical interconnect modules. The four rows (522A-522D) of optical interconnect modules are cooled by two “L” shaped module heat sinks (524A and 524B), which fit over the top of the optical interconnect modules as shown in Fig. 6. Module heat sink (524A) fits over rows (522A and 522B) and module heat sink (524B) fits over rows (522C and 522D). Each module heat sink may be liquid cooled and may have a coolant inlet (526) and a coolant outlet (528). The IC die (504) may have a separate IC die heat sink (530). The IC die heat sink (530) may be liquid cooled and may fit over a stiffener (520) that provides mechanical rigidity to a IC package substrate on which the IC die (504) is mounted. Both the module heat sinks (524A and 524B) and the IC die heat sink (530) may be secured to the host PCB (508) with fasteners.Attorney Docket No. P3153-PCT

[0115] An advantage of any of the previously described embodiments of an optical interconnect module is that the optical interconnect module is mateable / unmateable from the underlying substrate. This contrasts with some prior art systems in which the optical module is permanently mounted, for example, with solder, to the underlying substrate. The mateability of the embodiments described herein allows replacement of defective optical interconnect modules without damage to or reworking the underlying substrate.

[0116] The previous description has generally described an optical interconnect module having a Si-Fly™ connector interface configured to mate with a Si-Fly™ connector base soldered to an underlying substrate; however, in other embodiments the Si-Fly™ connector base may be omitted, and the optical interconnect module may make a direct electrical connection to pads of an underlying substrate without the base. For example, some form of conductive paste or conductive elastomer may be used between a bottom of the optical interconnect module and the pads of the underlying substrate. Compressive hardware would be required to force the optical interconnect module against the pads of the underlying substrate.

[0117] While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. The descriptions are not intended to limit the scope of the invention to the particular forms set forth herein. To the contrary, the present descriptions are intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and otherwise appreciated by one of ordinary skill in the art.

[0118] For example, while the terms 'transceiver' and 'optical transceiver' may be used throughout this disclosure for consistency with common industry terminology, it should be understood that the described devices and methods are equally applicable to optical interconnect modules, systems and / or arrangements that may function as transceivers, transmitters, or receivers. The thermal management approaches, and integration techniques presented herein can be adapted for any of these operational modes, providing flexibility in deployment while maintaining the fundamental advantages of the disclosed embodiments.

[0119] Additionally, while specific implementations utilizing the Si-Fly™ connector interface have been detailed, the folding and modular architectures described herein may be adapted to workAttorney Docket No. P3153-PCTwith other high-speed connector interfaces while maintaining the core benefits of thermal efficiency, signal integrity, and manufacturing simplicity. Similarly, while specific implementations of electrooptic components and thermal management structures have been described, other arrangements that preserve the fundamental relationships between electrical paths, optical paths, and thermal paths may be employed while remaining within the scope of the present disclosure. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

Attorney Docket No. P3153-PCTCLAIMS1. A foldable optical interconnect module having an open configuration and a closed configuration, comprising:a connector interface configured to provide electrical connections to a host printed circuit board (PCB);a flexible circuit comprising conductive layers for routing electrical signals, the flexible circuit extending from the connector interface to at least one optical carrier assembly, the at least one optical carrier assembly integrating electrooptic components, the electrooptic components including a laser light source or a photodetector;at least one optical block having an alignment interface for optical signal routing, and at least one heat spreader disposed to provide a thermal dissipation path from the at least one optical carrier assembly to an external heat dissipating surface.

2. The foldable optical interconnect module of claim 1, wherein the flexible circuit is symmetric about a plane of symmetry, and wherein the at least one optical carrier assembly comprises a first optical carrier assembly and a second optical carrier assembly disposed on opposite sides of the plane of symmetry.

3. The foldable optical interconnect module of claim 1, wherein the connector interface includes an array of high-speed electrical contacts and additional power and control signal contacts.

4. The foldable optical interconnect module of claim 1, wherein the conductive layers of the flexible circuit are arranged in a multilayer structure for electrical signal routing.

5. The foldable optical interconnect module of claim 1, wherein the at least one heat spreader is made of a thermally conductive material and is mechanically coupled to the at least one optical carrier assembly.

6. The foldable optical interconnect module of claim 5, wherein:in the open configuration, the at least one optical carrier assembly and the at least one optical block are exposed to allow assembly and alignment; andAttorney Docket No. P3153-PCTin the closed configuration, the optical interconnect module is folded into a compact form, with the at least one heat spreader forming a flat surface for attachment to the external heat dissipating surface.

7. The foldable optical interconnect module according to any one of claims 1-6, wherein the connector interface is a Si-Fly™ connector interface.

8. A modular optical interconnect module, comprising:a plurality of stackable sub-modules, each sub-module including integrated optical elements, printed circuit board (PCB) assemblies, and heat spreaders;a common thermal interface formed by the heat spreaders of the plurality of stackable submodules arranged adjacent to one another to provide a continuous heat dissipation path; interconnect elements configured to distribute power and control signals across the stacked sub-modules, andfiber routing structures enabling vertical fiber egress from each sub-module, wherein the modular optical interconnect system is configured to allow scalable channel counts by adding or removing sub-modules.

9. The modular optical interconnect module of claim 8, wherein the heat spreader of each submodule comprises a T-shaped body having an extended arm configured to contact the integrated optical elements and a cap configured to form a portion of the common thermal interface.

10. The modular optical interconnect module of claim 9, wherein the cap comprises a cutout configured to allow the vertical fiber egress from the sub-module.

11. The modular optical interconnect module of claim 8, further comprising a power and control printed circuit board oriented parallel to the plurality of stackable sub-modules, wherein the interconnect elements comprise conductive pins extending orthogonally from the power and control printed circuit board through the stackable sub-modules.Attorney Docket No. P3153-PCT12. The modular optical interconnect module of claim 8, wherein the fiber routing structures employ a pigtailed fiber configuration with optical fibers permanently integrated into each submodule.

13. The modular optical interconnect module of claim 12, wherein the pigtailed fiber configuration enables pre-assembly and testing of each sub-module with its optical connections intact.

14. The modular optical interconnect module of claim 12, wherein the pigtailed fiber configuration maintains fixed optical alignment within each sub-module.

15. The modular optical interconnect module of claim 12, wherein:each sub-module is pre-assembled and tested with its pigtailed optical fibers;the pre-tested sub-modules are stacked to form the modular optical interconnect system; and the pigtailed fibers from each sub-module maintain vertical egress in the stacked configuration.

16. The modular optical interconnect module of claim 8, wherein the common thermal interface is compatible with liquid cooling systems for enhanced thermal management.

17. The modular optical interconnect module of claim 8, wherein the heat spreaders in each submodule are configured to independently dissipate heat generated by the optical elements.

18. The modular optical interconnect module of any of claims 8-17, wherein the integrated PCB assemblies include embedded ground planes to minimize electrical noise and maintain signal integrity.

19. The modular optical interconnect module of claim 18, wherein the interconnect elements include power and control signal contacts.

20. An optical interconnect system, comprising:a connector interface comprising an array of cavities and configured to provide electrical connections to a host printed circuit board (PCB);Attorney Docket No. P3153-PCTelectrooptic components configured to convert between electrical and optical signals; a thermal management structure providing a thermal path between the electrooptic components and configured to mate with an external cooling system; anda signal distribution structure comprising:electrical pathways extending from the connector interface to the electrooptic components;optical fiber pathways extending in a direction perpendicular to the electrical pathways; andthermal conduction pathways extending from the electrooptic components to the external cooling system;wherein the electrical pathways, optical fiber pathways, and thermal conduction pathways are arranged to fit within a footprint defined by the connector interface.

21. The optical interconnect system of claim 20, wherein:a first portion of the array of cavities contain high-speed differential signal contacts; and a second portion of the array of cavities contain power and control signal contacts.

22. The optical interconnect system of claim 20, wherein the electrooptic components comprise:vertical-cavity surface-emitting lasers (VCSELs) for converting electrical signals to optical signals; andphotodiodes for converting optical signals to electrical signals.

23. The optical interconnect system of claim 20, wherein the thermal management structure comprises:heat spreaders thermally coupled to the electrooptic components; anda thermal interface configured to couple with an external heat dissipating surface.

24. The optical interconnect system of any of claims 20-23, wherein:the electrical pathways extend in a first direction from the connector interface; and the thermal conduction pathways extend in a second direction, substantially opposite to the first direction, optimized for heat transfer to the external cooling system.Attorney Docket No. P3153-PCT25. A method of manufacturing an optical interconnect module, comprising:providing a connector interface configured to mate with a host printed circuit board (PCB); arranging electrooptic components for signal conversion;implementing thermal management structures for heat dissipation;establishing signal routing between the connector interface and the electrooptic components; andconfiguring the electrooptic components, thermal management structures, and signal routing to maintain a footprint substantially defined by the connector interface.

26. The method of claim 25, wherein implementing thermal management structures comprises:positioning heat spreaders in direct thermal contact with the electrooptic components; and providing a thermal interface configured for connection to an external cooling system.

27. The method of claim 25, wherein establishing signal routing comprises:routing electrical signals from the connector interface to the electrooptic components along a first path; androuting optical signals from the electrooptic components along a second path substantially perpendicular to the first path.

28. The method of claim 25, further comprising:providing access for optical alignment and fiber attachment during assembly; and enabling testing of optical performance before final assembly completion.

29. The method of claim 25, wherein the connector interface includes both high-speed differential signals and power / control signals within a single connector footprint.

30. An optical interconnect system, comprising:a connector base configured to mate with a host circuit board;multiple optical conversion modules, each optical conversion module comprising a connector interface, electrooptic components and associated thermal management structures;Attorney Docket No. P3153-PCTsignal routing elements coupling the connector base to the optical conversion modules; and a unified thermal interface providing thermal coupling between the optical conversion modules and an external cooling system.

31. The optical interconnect system of claim 30, wherein:each optical conversion module is independently testable prior to system integration; and the system is configurable for different channel counts by varying the number of optical conversion modules.

32. The optical interconnect system of claim 30, wherein the signal routing elements comprise:interconnect elements for distributing power and control signals between modules; and signal integrity structures for maintaining high-speed signal performance across the modules.

33. The optical interconnect system of claim 30, further comprising:fiber routing structures configured to direct optical fibers from the optical conversion modules while maintaining the system footprint defined by the connector base.

34. The optical interconnect system of any of claims 30-33, wherein the unified thermal interface comprises:local heat spreading elements within each optical conversion module; anda common thermal structure coupling the local heat spreading elements to the external cooling system.

35. A high-density optical interconnect arrangement, comprising:multiple optical interconnect modules arranged to interface with a processing unit;a common cooling interface extending across the optical interconnect modules and the processing unit;signal routing structures maintaining signal integrity while enabling dense placement of the optical interconnect modules; andAttorney Docket No. P3153-PCTfiber routing structures directing optical fibers to prevent interference between adjacent optical interconnect modules.

36. The high-density optical interconnect arrangement of claim 35, wherein the multiple optical interconnect modules are arranged in a plurality of rows, and wherein the common cooling interface comprises at least one L-shaped heat sink configured to span across and cool two adjacent rows of the optical interconnect modules.

37. The high-density optical interconnect arrangement of claim 35, wherein:each optical interconnect module maintains direct thermal contact between its electrooptic components and the common cooling interface; andthe common cooling interface provides liquid cooling across the arrangement.

38. The high-density optical interconnect arrangement of claim 35, wherein the signal routing structures comprise:high-speed differential pairs maintained within controlled impedance environments; and power and control signal routing integrated within connector interfaces of each optical interconnect module.

39. The high-density optical interconnect arrangement of claim 35, wherein:the fiber routing structures direct optical fibers in a direction perpendicular to a plane of the processing unit; andadjacent optical interconnect modules share thermal and mechanical interfaces while maintaining optical isolation.

40. The high-density optical interconnect arrangement of any of claims 35-39, wherein:the optical interconnect modules are arranged around a periphery of the processing unit; andthe common cooling interface provides cooling across both the optical interconnect modules and the processing unit.Attorney Docket No. P3153-PCT41. The high-density optical interconnect arrangement of any of claims 35-39, wherein:the optical interconnect modules are arranged around a periphery of the processing unit; a first cooling system is configured to maintain the optical interconnect modules at a first operating temperature range; anda second cooling system, separate from the first cooling system, is configured to maintain the processing unit at a second operating temperature range higher than the first operating temperature range.

42. A foldable optical interconnect module, comprising:a base portion comprising an electrical connector interface;a flexible circuit portion extending from the base portion;an optical conversion portion coupled to the flexible circuit portion and comprising electrooptic components; anda thermal dissipation portion thermally coupled to the electrooptic components; wherein the flexible circuit portion is configured to enable the optical conversion portion to fold relative to the base portion while maintaining electrical connectivity.

43. The foldable optical interconnect module of claim 42, wherein:in an unfolded configuration, the optical conversion portion and flexible circuit portion extend horizontally from the base portion to facilitate electrooptic component assembly and fiber attachment; andin a folded configuration, the optical conversion portion is positioned above the base portion such that the footprint is substantially defined by the base portion, while maintaining thermal contact with an external cooling system.

44. The foldable optical interconnect module of claim 42, wherein the flexible circuit portion comprises:multiple conductive layers for routing electrical signals;controlled impedance structures for maintaining signal integrity through the fold; and mechanical features accommodating thermal expansion differences between components.Attorney Docket No. P3153-PCT45. The foldable optical interconnect module of claim 42, wherein the thermal dissipation portion comprises:heat spreaders in direct thermal contact with the electrooptic components; anda substantially planar upper surface formed in the folded configuration for interfacing with an external heat dissipating surface.

46. The foldable optical interconnect module of claim 42, wherein:the electrical connector interface comprises an array of cavities, a first portion of the cavities containing high-speed differential contacts and a second portion of the cavities containing power and control signal contacts;andthe folded configuration maintains signal integrity for high-speed transmission while enabling direct thermal contact between the electrooptic components and an external cooling system.

47. The foldable optical interconnect module of claim 42, further comprising:optical fibers coupled to the optical conversion portion; andfiber routing structures directing the optical fibers horizontally when in the folded configuration.

48. The foldable optical interconnect module of claim 42, wherein:the optical conversion portion comprises an optical carrier assembly integrating verticalcavity surface-emitting lasers and photodiodes;the optical carrier assembly includes alignment features for optical coupling; and the folded configuration maintains precise alignment while enabling thermal coupling to an external cooling system.

49. The foldable optical interconnect module of any of claims 42-48, wherein multiple foldable optical interconnect modules are configured to:arrange around a periphery of a processing unit;share a common heat dissipating surface; andAttorney Docket No. P3153-PCTmaintain signal integrity while enabling high-density placement.

50. A foldable optical interconnect module, comprising:a connector interface configured to mate with a host printed circuit board;an optical carrier assembly comprising electrooptic components for converting between electrical and optical signals;flexible circuitry electrically coupling the connector interface to the optical carrier assembly;heat spreaders thermally coupled to the optical carrier assembly and configured to interface with an external cooling system; andan optical interface block comprising a standardized optical connector interface configured to enable mateable and unmateable connections of optical fibers;wherein the flexible circuitry enables the optical carrier assembly and the optical interface block to fold relative to the connector interface into an operational configuration where the optical connector interface is accessible for fiber connection and disconnection while maintaining thermal contact between the heat spreaders and the external cooling system.

51. The foldable optical interconnect module of claim 50, wherein the standardized optical connector interface comprises an MT connector interface oriented perpendicular to a mating direction of the connector interface.

52. The foldable optical interconnect module of claim 50, wherein: in an unfolded configuration, the optical carrier assembly and optical interface block extend horizontally from the connector interface to facilitate initial optical fiber attachment; and in the operational configuration, the heat spreaders form a substantially planar surface for thermal coupling to the external cooling system.

53. The foldable optical interconnect module of claim 50, wherein the optical connector interface is configured to enable removal and replacement of optical fibers without requiring realignment of electrooptic components within the optical carrier assembly.

54. The foldable optical interconnect module of claim 50, wherein:Attorney Docket No. P3153-PCTthe connector interface comprises an array of high-speed electrical contacts;the electrooptic components comprise vertical -cavity surface-emitting lasers and photodiodes; andthe heat spreaders provide a direct thermal path between the electrooptic components and the external cooling system.

55. A system comprising:multiple foldable optical interconnect modules according to claim 46, arranged around a periphery of a processing unit; anda common heat dissipating surface extending across the foldable optical interconnect modules and the processing unit,wherein each foldable optical interconnect module maintains individually serviceable optical connections while sharing the common heat dissipating surface.

56. The system of claim 55, wherein the multiple foldable optical interconnect modules are arranged in a plurality of rows around the periphery of the processing unit, and wherein the common heat dissipating surface extends across the plurality of rows.

57. An electrical interconnection system, comprising:a housing defining cavities arranged in an array;ground shield structures between the cavities;electrical contacts disposed within the cavities for carrying signals; andconnection elements configured to selectively mate with:i) an optical conversion module comprising electrooptic components for converting between electrical and optical signals, orii) a cable connector for electrical signal transmission.

58. The electrical interconnection system of claim 57, wherein the connection elements comprise: mounting elements configured to mount the optical conversion module in a folded configuration where a flexible circuit electrically couples the electrical contacts to electrooptic components positioned above the housing.Attorney Docket No. P3153-PCT59. The electrical interconnection system of claim 57, wherein the connection elements comprise: mounting elements configured to stack optical conversion sub-modules above the housing while maintaining electrical connections through the cavities.

60. The electrical interconnection system of claim 57, wherein: the ground shield structures form an egg-crate configuration separating adjacent cavities; and the ground shield structures are configured to electrically connect to corresponding ground structures in either the optical conversion module or the cable connector.

61. The electrical interconnection system of claim 57, further comprising: auxiliary connection elements configured to provide power and control signals to the optical conversion module separate from the signals carried by the electrical contacts.

62. The electrical interconnection system of claim 58, wherein:the optical conversion module comprises a heat spreader forming a substantially planar upper surface when in the folded configuration; andthe planar upper surface is configured to thermally couple with an external cooling system.

63. The electrical interconnection system of claim 58, wherein:the optical conversion module comprises an optical interface block configured to route optical fibers in a direction perpendicular to a mating direction of the electrical contacts when in the folded configuration.

64. The electrical interconnection system of claim 59, further comprising:interconnect elements configured to distribute power and signals between the stacked optical conversion sub-modules.

65. The electrical interconnection system of claim 59, wherein:each optical conversion sub-module comprises heat spreaders; andAttorney Docket No. P3153-PCTthe stacked optical conversion sub-modules share a common thermal interface spanning across the sub-modules.

66. The electrical interconnection system of claim 59, wherein:the optical conversion sub-modules are configured to route optical fibers vertically away from the housing to enable dense lateral packing of multiple electrical interconnection systems.

67. The electrical interconnection system of claim 59, wherein:the optical conversion sub-modules comprise optical connector interfaces configured to enable removal and replacement of optical fibers.

68. The electrical interconnection system of claim 67, wherein:the optical connector interfaces are arranged in a single or two-row configuration corresponding to the array of cavities in the housing.

69. The electrical interconnection system of claim 67, wherein:the optical conversion sub-modules are assembled into a stack;the stack is held together by mechanical compression elements configured to: maintain thermal contact between the sub-modules and a common thermal interface, ensure reliable electrical connections through interconnect elements, andenable disassembly of the stack for maintenance or replacement of individual sub-modules.

70. The electrical interconnection system of claim 59, wherein:the optical conversion sub-modules comprise permanently integrated optical fibers configured for vertical egress from the housing.

71. The electrical interconnection system of claim 70, wherein:the permanently integrated optical fibers are configured for vertical egress to enable dense lateral placement of the optical conversion sub-modules adjacent to electrical interconnection modules.Attorney Docket No. P3153-PCT72. An optical interconnect system, comprising:a host printed circuit board;a connector base mounted on the host printed circuit board and comprising an array of high-speed differential signal contacts;auxiliary power and control cables separate from the connector base; andan optical interconnect module comprising:a connector interface configured to mate with the connector base, the connector interface comprising an array of high-speed differential signal contacts;electrooptic components configured to convert between electrical and optical signals;a thermal management structure providing a thermal path between the electrooptic components and an external cooling system;high-speed signal pathways coupled to the connector interface; and power and control pathways coupled to the auxiliary power and control cables.

73. The optical interconnect system of claim 72, wherein:the connector interface comprises an egg-crate shield structure with ground planes separating differential signal pairs; andthe auxiliary power and control cables are routed separately from the high-speed signal pathways to minimize electrical interference.

74. The optical interconnect system of claim 72, wherein:the optical interconnect module comprises either a foldable optical interconnect module or a modular optical interconnect module;the foldable optical interconnect module includes flexible circuitry coupling the connector interface to the electrooptic components; andthe modular optical interconnect module includes stackable sub-modules with interconnect elements for distributing the power and control signals.

75. The optical interconnect system of claim 72, wherein:Attorney Docket No. P3153-PCTthe auxiliary power and control cables are permanently attached to the optical interconnect module to optimize reliability; andthe connector interface is configured to mate and unmate independently of the auxiliary power and control cables.

76. The optical interconnect system of claim 72, wherein:multiple optical interconnect systems are arranged around a periphery of a processing unit mounted on the host printed circuit board;the auxiliary power and control cables are routed to avoid interference with adjacent optical interconnect modules; andthe optical interconnect modules share a common cooling interface extending across the processing unit.

77. A method of using an optical interconnect module, comprising:receiving electrical signals from a host circuit board through a high-speed electrical interface;performing electrical-to-optical signal conversion using electro-optical conversion elements;outputting optical signals through optical transmission media in a direction perpendicular to a mating direction of the electrical interface; andtransferring heat generated during signal conversion to an external cooling system.

78. The method of claim 77, further comprising:providing power and control signals through auxiliary transmission paths separate from the high-speed electrical interface; andmaintaining signal integrity by isolating the auxiliary transmission paths from high-speed signal paths.

79. A method of using a modular optical interconnect system, comprising:arranging multiple signal conversion modules in a stacked configuration above an electrical interface;Attorney Docket No. P3153-PCTdistributing electrical signals between the stacked modules through electrical interconnection elements;routing optical transmission media vertically from each module; andtransferring heat through thermal conduction elements to a shared thermal management interface.

80. The method of claim 79, further comprising:validating operation of each signal conversion module individually prior to stacking; verifying optical coupling alignment within each module; andmaintaining the verified alignment during assembly of the stacked configuration.

81. A method of using multiple optical interconnect modules in a high-density configuration, comprising:positioning multiple optical interconnect modules around a processing element; routing optical transmission media from each module to prevent signal interference between adjacent modules; andthermally coupling signal conversion elements of each module to a shared thermal distribution element.

82. The method of claim 81, further comprising removing heat from both the optical interconnect modules and the processing element using a common thermal management system.

83. The method of claim 81, further comprising:enabling independent access to optical connections for each module while maintaining shared thermal management; andoptimizing thermal performance by providing efficient heat transfer between the signal conversion elements and the thermal management system.

84. An optical interconnect module comprising:an optical interconnect portion comprising electrooptic components;a connector interface configured to mate with a host PCB; andAttorney Docket No. P3153-PCTan auxiliary cable separate from the connector interface, wherein the auxiliary cable carries power and control signals.

85. The optical interconnect module of claim 84, wherein the auxiliary cable is configured to transmit power from the host PCB to the optical interconnect module.

86. The optical interconnect module of claim 84, comprising:high-speed signal pathways coupled to the connector interface; andpower and control pathways coupled to the auxiliary cable and separate from the highspeed signal pathways;wherein the optical interconnect module is configured to transmit high-speed signals through the connector interface and is configured to transmit power and control signals through the auxiliary cable.

87. The optical interconnect module of claim 86, wherein the connector interface and the auxiliary cable are separate connectors.

88. The optical interconnect module of claim 84, comprising optical fibers for carrying optical signals.

89. The optical interconnect module of claim 84, comprising a printed circuit board.

90. The optical interconnect module of claim 84, wherein the auxiliary cable is permanently attached to the optical interconnect module.

91. The optical interconnect module of claim 84, comprising an optical interface block.

92. The optical interconnect module of claim 91, wherein the optical interface block provides a standardized multifiber optical interface.

93. An optical interconnect system comprising:Attorney Docket No. P3153-PCTa host PCB;a connector base mounted on the host PCB;an optical interconnect module configured to mate with the connector base, comprising: electrooptic components for signal conversion;a connector interface; andan auxiliary cable carrying power and control signals.

94. The optical interconnect system of claim 93, wherein the auxiliary cable is configured to transmit power to the optical interconnect module.

95. The optical interconnect system of claim 93, wherein:the host PCB provides power to the optical interconnect module through the auxiliary cable.

96. The optical interconnect system of claim 93, wherein:the optical interconnect module comprises high-speed signal pathways coupled to the connector base and power and control pathways coupled to the auxiliary cable; andthe optical interconnect module is configured to transmit high-speed signals through the connector base and is configured to convey power and control signals through the auxiliary cable.

97. The optical interconnect system of claim 93, wherein the auxiliary cable is permanently attached to the optical interconnect module.

98. The optical interconnect system of claim 93, comprising an optical interface block providing a standardized multifiber optical interface.

99. The optical interconnect system of claim 93, comprising:multiple connector bases mounted on the host PCB; andmultiple optical interconnect modules configured to mate with the multiple connector bases.

100. A high-density interconnect arrangement, comprising:Attorney Docket No. P3153-PCTan integrated circuit (IC) die mounted on an TC package substrate, wherein the IC package substrate is mounted on a host printed circuit board (PCB);a plurality of interconnect modules co-packaged with the IC die, each configured to mate with the IC package substrate via a high-speed interface, the interconnect modules comprising electrical interconnect modules and / or optical interconnect modules, the interconnect modules being arranged in a pattern along the sides the IC die; anda plurality of cables extending from each interconnect module to carry optical or electrical signals, wherein the cables extend primarily from one side of each respective interconnect module.

101. The high-density interconnect arrangement of claim 100, wherein the plurality of cables comprise optical cables in the form of a ribbon cable having a plurality of optical fibers distributed in parallel rows.

102. The high-density interconnect arrangement of claim 100, wherein each interconnect module includes high-speed differential signal contacts and lower-speed power and control contacts that are routed through a single interface, wherein the single interface carries both high-speed signals and power / control signals.

103. The high-density interconnect arrangement of claim 100, wherein each interconnect module is provided witha primary high-speed connector carrying high-speed differential signals; anda secondary connector positioned adjacent to or on a side of the interconnect module facing away from the IC package substrate to carry power and low-speed control signals, wherein the primary high-speed connector is reserved for data signals, and the secondary connector distributes power and control signals from the IC package substrate or host PCB.

104. The high-density interconnect arrangement of claim 100, wherein each interconnect module comprises:a high-speed interface configured to mate with a connector on the IC package substrate for data signals; andAttorney Docket No. P3153-PCTan auxiliary ribbon or flex cable extending from a housing of the interconnect module for conveying power and low-speed control signals to or from the IC package substrate or host PCB, the auxiliary cable being connected to a separate receptacle or terminal area on the IC package substrate or host PCB, distinct from the high-speed interface.

105. The high-density interconnect arrangement of any one of claims 100-104, wherein the IC package substrate is configured to provide:a common mechanical interface for high-speed connectors around the IC die; and one or more additional headers, receptacles, or cable attachments for receiving low-speed / power connectors or auxiliary cables, thereby enabling interchangeable routing options for non-high-speed signals without altering an arrangement of high-speed signal contacts.

106. The high-density interconnect arrangement of claim 100, further comprising a stiffener extending in a frame-like arrangement around the IC die and between rows of the interconnect modules to reduce warping of the IC package substrate.

107. The high-density interconnect arrangement of claim 100, wherein the interconnect modules comprise:optical interconnect modules, each connected to fewer cables than the electrical interconnect modules; andelectrical interconnect modules, each connected to a larger number of cables than the optical interconnect modules,wherein the fewer cables connected to the optical interconnect modules provide simplified cable management.

108. An optical interconnect module comprising:a first optical interface configured to provide optical communication between a first electrooptic component and a first group of optical fibers,a second optical interface configured to provide optical communication between a second electrooptic component and a second group of optical fibers, wherein the first optical interface isAttorney Docket No. P3153-PCTindependently connected to the first group of optical fibers and the second optical interface is independently connected to the second group of optical fibers;a first heat spreader in thermal communication with the first electrooptic component; and a second heat spreader in thermal communication with the second electrooptic component, wherein a top surface of the first heat spreader and a top surface of the second heat spreader form a common thermal interface configured to dissipate heat from the first electrooptic component and the second electrooptic component to an external heat sink.

109. The optical interconnect module of claim 108, wherein the first optical interface and the second optical interface are spatially separated such that they are configured to be independently mated and unmated from the first group of optical fibers and the second group of optical fibers, respectively.

110. The optical interconnect module of claim 108, further comprising a flexible circuit having a plane of symmetry, wherein the first electrooptic component and the second electrooptic component are disposed on opposite sides of the plane of symmetry.

111. The optical interconnect module of claim 108, wherein the first heat spreader and the second heat spreader are mechanically separable but aligned to form a substantially planar continuous surface at the common thermal interface.

112. The optical interconnect module of claim 108, further comprising a connector interface configured to mate with a host printed circuit board, wherein the first and second groups of optical fibers extend in a direction perpendicular to a mating direction of the connector interface.

113. An optical interconnect module comprising:a mateable / unmateable electrical interface comprising an array of differential signal pairs with each differential signal pair in a cavity surrounded by a ground shield;a first electrooptic component in electrical communication with a first portion of the array of differential signal pairs configured to perform an optical-to-electrical or electrical-to-optical conversion;Attorney Docket No. P3153-PCTa second electrooptic component in electrical communication with a second portion of the array of differential signal pairs configured to perform an optical-to-electrical or electrical-to-optical conversion, wherein the second electrooptic component is spatially separated from the first electrooptic component; anda common thermal interface configured to dissipate heat from the first electrooptic component and the second electrooptic component.

114. The optical interconnect module of claim 113, further comprising a flexible circuit electrically connecting the electrical interface to the first and second electrooptic components, wherein the flexible circuit is folded such that the common thermal interface is positioned above the electrical interface.

115. The optical interconnect module of claim 113, wherein the first electrooptic component is housed in a first sub-module and the second electrooptic component is housed in a second submodule, and wherein the first and second sub-modules are stacked adjacent to each other.

116. The optical interconnect module of claim 113, further comprising an auxiliary electrical connection separate from the mateable / unmateable electrical interface, wherein the auxiliary electrical connection is configured to carry power and control signals to the first and second electrooptic components.

117. The optical interconnect module of claim 113, wherein the mateable / unmateable electrical interface comprises interlocking plates that define the cavities and serve as the ground shield.

118. A method of making an optical connection to an optical interconnect module comprising:placing the optical interconnect module in an open position;connecting a fiber ferrule to an optical interface of the optical interconnect module; and folding a flexible circuit of the optical interconnect module to place the optical interconnect module in a closed position.Attorney Docket No. P3153-PCT119. The method of claim 118, wherein placing the optical interconnect module in the closed position brings a heat spreader of the optical interconnect module into an orientation forming a flat upper surface for thermal coupling.

120. The method of claim 118, wherein connecting the fiber ferrule comprises connecting a first fiber ferrule to a first optical interface and a second fiber ferrule to a second optical interface while the flexible circuit is substantially straight and unbent.

121. The method of claim 118, further comprising mounting the optical interconnect module to a host substrate via a high-speed electrical connector prior to folding the flexible circuit.

122. The method of claim 118, wherein the optical interface is oriented to route optical fibers horizontally and perpendicular to a mating direction of the optical interconnect module when in the closed position.

Images