Light engine structure, communication device and data center system

Abstract

The embodiment of the present application relates to a kind of light engine structure, communication equipment and data center system, the light engine structure, comprising: drive chip, the drive chip includes driving circuit and welding electrode, the drive chip is used to be connected with substrate or PCB board by gold wire bonding mode;Flip VCSEL including lens structure, the flip VCSEL including lens structure is welded on the welding electrode of the drive chip, and is electrically connected with the driving circuit;Wherein, the flip VCSEL including lens structure includes VCSEL chip and lens structure integrated on the substrate of the VCSEL chip;The lens structure is located on the light path of the VCSEL chip, for the light emitted by the VCSEL chip is collimated or focused.

Description

Technical Field

[0001] This application relates to the field of optoelectronic packaging technology, and in particular to optical engine structures, communication equipment, and data center systems. Background Technology

[0002] With the rapid development of data centers, high-performance computing, and artificial intelligence applications, the demand for high-speed optical interconnect technology is increasing. Traditional optical engine structures typically use upright VCSEL chips and connect them to the driver circuit via wire bonding.

[0003] However, due to factors such as signal integrity, heat dissipation efficiency, package size, and coupling efficiency, this connection method makes it difficult to simultaneously ensure normal electrical connection and compact chip arrangement density in multi-channel array design, making it unsuitable for large-scale high-speed optical transmission arrays. Summary of the Invention

[0004] The main objective of this invention is to provide a light engine structure, communication device, and data center system, which aims to solve the aforementioned technical problems in the prior art.

[0005] Therefore, it is necessary to provide a light engine structure and its fabrication method to address the aforementioned technical problems.

[0006] In a first aspect, this application provides a light engine structure, including: A driver chip, comprising a driver circuit and a welding electrode; the driver chip is used to connect to a substrate or PCB board via gold wire bonding. A flip-chip VCSEL with a lens structure is soldered to the soldering electrode of the driver chip and electrically connected to the driver circuit. The flip-chip VCSEL with lens structure includes a VCSEL chip and a lens structure integrated on the substrate of the VCSEL chip; the lens structure is located in the light emission path of the VCSEL chip and is used to collimate or focus the light emitted by the VCSEL chip.

[0007] In one embodiment, the lens structure is one of a convex lens, a microlens, or a Fresnel lens, and the lens structure is integrally formed with the substrate or formed on the surface of the substrate through an additional process.

[0008] In one embodiment, the lens structure is a concave convex lens, wherein the concave convex lens forms a recessed structure on the substrate surface through an etching process, and the recessed structure has the optical effect of a convex lens.

[0009] In one embodiment, the substrate thickness of the concave convex lens ranges from 0.15 to 0.4, the radius of curvature ranges from -0.08 to -0.2, and the conic coefficient ranges from -0.4 to -1.5.

[0010] In one embodiment, the optical axis of the lens structure is aligned with the center of the light-emitting region of the VCSEL chip.

[0011] In one embodiment, the optical engine structure further includes an optical fiber, the light input end of which is coupled to the light output side of the flip-chip VCSEL with lens structure, for receiving the optical signal processed by the lens structure.

[0012] In one embodiment, the optical fiber is aligned and coupled to the flip-chip VCSEL containing the lens structure via an optical fiber connector or directly.

[0013] In one embodiment, the driver chip further includes a control circuit for controlling the drive current and operating state of the flip-chip VCSEL with lens structure.

[0014] Secondly, this application also provides a communication device, a host computer, and a motherboard; and The light engine structure as described in any of the above embodiments is connected to the motherboard.

[0015] In one possible implementation, the light engine structure is detachably connected to the motherboard.

[0016] Thirdly, this application also provides a data center system, including: Server racks; and, The communication device as described in any of the above, wherein the communication device is located in the cabinet.

[0017] The present invention has at least the following beneficial effects: The optical engine structure provided by this invention achieves multi-dimensional technical benefits, including structural simplification, performance improvement, cost reduction, and application expansion, through an innovative integrated design of a driver chip and a flip-chip VCSEL with a lens structure. Specifically, by directly integrating the lens structure onto the VCSEL chip substrate, the additional space occupied by independent lens components in traditional solutions is avoided, resulting in a more compact overall structure and a compact, integrated design suitable for large-scale high-speed optical transmission arrays. The lens structure integrated into the substrate effectively reduces the VCSEL's beam divergence angle, collimating or focusing the originally dispersed beam, thus improving beam quality and energy concentration. By using gold wire bonding to connect the driver chip to the substrate / PCB, and with the VCSEL directly soldered to the driver chip electrodes, the electrical connection path is significantly shortened, effectively reducing parasitic inductance and capacitance. Through simplified structure and optimized process, the manufacturing cost of the optical engine is significantly reduced, providing a cost basis for the large-scale popularization of various related devices. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the optical engine structure in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of a communication device in one embodiment of this application; Figure 3 This is an exploded view of a communication device according to an embodiment of this application.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] It is understood that the terms "first," "second," etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first client may be referred to as a second client, and similarly, a second client may be referred to as a first client.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. "Multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. "Several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0023] As described in the background section of this application, with the rapid development of data centers, high-performance computing, and artificial intelligence applications, the demand for high-speed optical interconnect technology is increasing. Traditional optical engine structures typically use upright VCSEL chips and connect them to the driving circuit via wire bonding.

[0024] However, due to factors such as signal integrity, heat dissipation efficiency, package size, and coupling efficiency, this connection method makes it difficult to simultaneously ensure normal electrical connection and compact chip arrangement density in multi-channel array design, making it unsuitable for large-scale high-speed optical transmission arrays.

[0025] In the upright structure, the heat generated in the light-emitting area needs to be conducted to the heat dissipation substrate through the substrate, resulting in high thermal resistance and low heat dissipation efficiency, which limits the power density of the device. In addition, in the upright structure, the light is emitted from the substrate side, requiring additional optical components for optical path adjustment, which increases system complexity and optical loss, and limits coupling efficiency.

[0026] In related technologies, there is a lack of optical engine architectures built on flip-chip technology, especially a lack of efficient optical coupling schemes under flip-chip structures. Therefore, how to achieve efficient optical coupling schemes under flip-chip architectures has become an urgent technical problem to be solved in this field.

[0027] Firstly, please refer to Figures 1-3 This application provides a light engine structure, including a driver chip, which includes a driver circuit and a bonding electrode. The driver chip is used to connect to a substrate or PCB board via gold wire bonding. A flip-chip VCSEL with a lens structure is also included, bonded to the bonding electrode of the driver chip and electrically connected to the driver circuit. The flip-chip VCSEL with the lens structure includes a VCSEL chip and a lens structure integrated on the substrate of the VCSEL chip. The lens structure is located in the light emission path of the VCSEL chip and is used to collimate or focus the light emitted by the VCSEL chip.

[0028] The following section will provide an example of a driver chip. For example, the driver chip, as the core control unit of the optical emission module, can be manufactured on a silicon substrate using CMOS technology. The thickness of the driver chip can be 300-500µm, and the specific size is determined according to the scale of the VCSEL array and packaging requirements, with typical sizes ranging from 1mm×1mm to 5mm×5mm.

[0029] For example, the driving circuit includes multiple independent current driving channels, each corresponding to a VCSEL unit. Each driving channel includes a current source, a modulation circuit, and a switching circuit; wherein, the current source is used to provide a stable DC bias current; the modulation circuit is used to convert the input electrical signal into a modulated current; and the switching circuit is used to control the opening and closing of the channel. The operating bandwidth of the driving circuit is greater than 1.5 times the required data transmission rate; for example, for a data transmission rate of 50Gbps, the bandwidth of the driving circuit should be greater than 75GHz.

[0030] For example, the welding electrodes are distributed on the upper surface of the driver chip and can adopt a multi-layer metal structure. A typical structure is as follows: the bottom layer is titanium (Ti) or chromium (Cr) with a thickness of 50-100 nm, used to form good adhesion with the silicon substrate; the middle layer is nickel (Ni) or platinum (Pt) with a thickness of 100-200 nm, serving as a barrier layer to prevent metal diffusion; and the top layer is gold (Au) with a thickness of 1-3 µm, used to form a reliable metallurgical bond with the solder. The diameter of the welding electrodes is 50-150 µm, and the spacing matches the electrode spacing of the VCSEL unit, typically 150-500 µm.

[0031] The following is an exemplary introduction to inverted VCSELs with lens structures. For example, a flip-chip VCSEL with a lens structure can be composed of multiple VCSEL units with lens structures arranged in a linear array or a two-dimensional array. The number of VCSEL units is determined according to application requirements, with typical configurations such as 1×4, 1×8, 1×12, 4×4, and 8×8.

[0032] The flip-chip VCSEL unit with lens structure includes a VCSEL chip, a substrate, and a lens structure integrated on the substrate.

[0033] For example, each VCSEL unit can employ a vertical-cavity surface-emitting structure, including a substrate, a lower DBR layer, an active region, an upper DBR layer, and electrodes. The substrate is made of gallium arsenide (GaAs) material with a thickness of 100-300 µm. For an 850 nm wavelength VCSEL, the substrate is transparent to the emission wavelength. The lower DBR layer consists of 20-40 pairs of AlGaAs / GaAs or AlAs / GaAs alternating layers, each pair having a thickness of one-quarter of the emission wavelength and a reflectivity greater than 99.5%. The active region adopts a multi-quantum-well structure, consisting of 3-5 InGaAs or GaAs quantum wells and an AlGaAs barrier layer, with a total thickness of 100-300 nm. The emission wavelength can be adjusted in the range of 780 nm-1100 nm by adjusting the quantum well composition and thickness. The upper DBR layer consists of 15-30 pairs of AlGaAs / GaAs alternating layers, with a reflectivity of approximately 99%. The electrodes include p-type electrodes and n-type electrodes. The p-type electrodes are located on the upper DBR layer, and the n-type electrodes are located on the back side of the substrate or the side of the lower DBR layer.

[0034] In the flip-chip structure, the VCSEL cell is flipped 180 degrees so that the p-type electrode faces downward and connects to the bonding electrode of the driver chip, with the substrate located on the light-emitting side. The substrate has a light-emitting window, which can be achieved by depositing an anti-reflection coating (material such as SiO2 / TiO2) on the substrate surface or by using surface microstructures (such as subwavelength gratings) to reduce Fresnel reflection loss.

[0035] For example, the substrate can be made of gallium arsenide (GaAs) material with a thickness of 100-300 micrometers and is transparent to the emission wavelength. The light-emitting surface of the substrate is polished to a surface roughness better than 10 nm.

[0036] The lens structure is integrated on the light-emitting surface of the substrate, located in the light-emitting path of the VCSEL chip. The lens structure can be a convex lens, a microlens, or a Fresnel lens, used to collimate or focus the diverging light emitted by the VCSEL chip.

[0037] For example, the parameters of the lens structure include radius of curvature, aperture, numerical aperture, and sagitta; wherein, the radius of curvature can be 50-500 micrometers; the aperture can be 30-200 micrometers; the numerical aperture can be 0.3-0.5; and the sagitta can be 5-50 micrometers.

[0038] The flip-chip bonding process can include solder bump preparation, alignment, and reflow soldering. Solder bump preparation can be achieved through electroplating, vapor deposition, or ball bonding. In electroplating, the bump pattern is defined by photolithography in wafer-level electroplating equipment, and gold-tin (Au80Sn20) alloy or tin-silver-copper (SAC305) alloy is electroplated, with bump diameters of 40-100 micrometers and heights of 20-60 micrometers. In vapor deposition, a solder layer with a thickness of 5-20 micrometers can be deposited using a mask. In ball bonding, pre-made solder balls with a diameter of 50-150 micrometers can be placed. During alignment, a high-precision flip-chip mounter can be used to align the flip-chip VCSEL with the driver chip, including the lens structure. Alignment accuracy requirements: XY direction error less than 5 micrometers, rotation error less than 0.5 degrees. The alignment process must ensure that the optical axis of the lens structure is aligned with the corresponding position of the driver chip. In the reflow soldering process, the aligned components are placed in a reflow oven for heating. Taking gold-tin solder as an example, the reflow soldering temperature profile is as follows: room temperature to 150°C (heating rate 2-3°C / second); 150°C to 280°C (heating rate 1-2°C / second); hold at 280°C for 30-60 seconds; cool to room temperature at 2-4°C / second; the shear strength after soldering is greater than 20g / bump, and the resistance is less than 10mΩ.

[0039] In other embodiments, the inverted VCSEL with lens structure can also be replaced by optical solutions such as multi-lens cascade structure, variable focal length lens, and multi-wavelength lens, which will not be described in detail here.

[0040] In this way, the flip-chip VCSEL structure with built-in lens can simplify the packaging process, improve optical coupling efficiency, reduce package size, enhance system reliability, and reduce costs.

[0041] In one embodiment, the lens structure is one of a convex lens, a microlens, or a Fresnel lens, and the lens structure is integrally formed with the substrate or formed on the surface of the substrate through an additional process.

[0042] The convex lenses used can be spherical convex lenses, aspherical convex lenses, concave convex lenses, etc.; the microlenses can be refractive microlenses, diffractive microlenses, or gradient refractive index microlenses.

[0043] The lens structure and the substrate are integrally formed, meaning the lens structure is directly formed from the substrate material through processing.

[0044] For example, the fabrication process for one-piece molding can be wet etching, dry etching, laser processing, etc.

[0045] In other embodiments, the lens structure may also be formed on the substrate surface by additional processes.

[0046] The types of additional processes can include material deposition and patterning processes, material deposition and patterning processes, nanoimprinting processes, etc.

[0047] For example, the material deposition and patterning process may include depositing a lens material (such as SiO2, TiO2, photoresist) on a substrate surface, and then forming a lens shape by photolithography and etching; wherein the deposition method includes PECVD, sputtering, evaporation, spin coating, etc.

[0048] For example, the microsphere self-assembly process may include self-assembling microspheres (such as SiO2 microspheres or polystyrene microspheres) onto the surface of a substrate as a lens unit; wherein the diameter of the microspheres is 1-100 micrometers.

[0049] For example, the nanoimprinting process may include using a mold with a lens pattern to imprint a lens structure onto a polymer material on the surface of a substrate.

[0050] In addition, lens structures can be replaced by binary optical lenses, superlenses, liquid lenses, etc., which will not be elaborated here.

[0051] In one embodiment, the lens structure is a concave convex lens, wherein the concave convex lens forms a recessed structure on the substrate surface through an etching process, and the recessed structure has the optical effect of a convex lens.

[0052] For example, a concave convex lens can be formed with a recessed structure on the substrate surface by an etching process.

[0053] The wet etching process can include steps such as photoresist patterning, etching, cleaning, and photoresist removal; while the dry etching process can use plasma to etch the substrate.

[0054] In addition, alternative solutions such as multi-stage concave lenses, graded concave lenses, and compound concave lenses can be used.

[0055] In one embodiment, the substrate thickness of the concave convex lens ranges from 0.15 to 0.4, the radius of curvature ranges from -0.08 to -0.2, and the conic coefficient ranges from -0.4 to -1.5.

[0056] The substrate thickness can be set to, for example, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc., the radius of curvature can be set to -0.08, -0.09, -0.1, -0.11, -0.12, -0.13, -0.14, -0.15, -0.16, -0.17, -0.18, -0.19, -0.2, and the conicity can be set to -0.4, -0.5, -0.6, -0.64, -0.7, -0.8, -0.9, -1, -1.1, -1.2, -1.3, -1.4, -1.5.

[0057] In one embodiment, the optical axis of the lens structure is aligned with the center of the light-emitting region of the VCSEL chip.

[0058] The methods for achieving optical axis alignment can include photolithographic alignment, laser direct writing alignment, and self-alignment processes.

[0059] For example, the photolithographic alignment steps may include alignment mark preparation, photolithographic alignment, exposure, and development.

[0060] For example, the laser direct writing alignment step may include identifying the light-emitting area and laser direct writing.

[0061] For example, the self-alignment process may include electrode alignment and mesa structure alignment.

[0062] In one embodiment, the optical engine structure further includes an optical fiber, the light input end of which is coupled to the light output side of the flip-chip VCSEL with lens structure, for receiving the optical signal processed by the lens structure.

[0063] The optical fiber can be single-mode or multimode.

[0064] In scenarios where the optical fiber is single-mode fiber, the core diameter can be 8-10µm and the cladding diameter is 125µm, which is suitable for long-distance, high-speed transmission. The typical model is SMF-28.

[0065] In scenarios where the optical fiber is multimode fiber, the core diameter is 50µm or 62.5µm and the cladding diameter is 125µm. It is suitable for short-distance, high-coupling-efficiency applications, with typical models being OM3 and OM4.

[0066] In one embodiment, the optical fiber is aligned and coupled to the flip-chip VCSEL containing the lens structure via an optical fiber connector or directly.

[0067] The types of fiber optic connectors can be LC connectors, SC connectors, MT connectors, and bare fiber optic adapters.

[0068] For example, the direct alignment coupling steps may include fiber end face processing, alignment, optical power monitoring, and fixing. Direct alignment coupling can save on connector size and cost.

[0069] In one embodiment, the driver chip further includes a control circuit for controlling the drive current and operating state of the flip-chip VCSEL with lens structure.

[0070] The functional modules of the control circuit may include a current control module, a modulation control module, an automatic power control module, a temperature compensation module, a protection module, etc.; the control method corresponding to the control circuit may include at least one of open-loop control, closed-loop control, digital control, and analog control.

[0071] In addition, the control function can also be implemented through external control chips, microcontrollers (MCUs), FPGAs, etc., which will not be elaborated here.

[0072] The present invention has at least the following beneficial effects: The optical engine structure provided by this invention achieves multi-dimensional technical benefits, including structural simplification, performance improvement, cost reduction, and application expansion, through an innovative integrated design of a driver chip and a flip-chip VCSEL with a lens structure. Specifically, by directly integrating the lens structure onto the VCSEL chip substrate, the additional space occupied by independent lens components in traditional solutions is avoided, resulting in a more compact overall structure and a compact, integrated design suitable for large-scale high-speed optical transmission arrays. The lens structure integrated into the substrate effectively reduces the VCSEL's beam divergence angle, collimating or focusing the originally dispersed beam, thus improving beam quality and energy concentration. By using gold wire bonding to connect the driver chip to the substrate / PCB, and with the VCSEL directly soldered to the driver chip electrodes, the electrical connection path is significantly shortened, effectively reducing parasitic inductance and capacitance. Through simplified structure and optimized process, the manufacturing cost of the optical engine is significantly reduced, providing a cost basis for the large-scale popularization of various related devices.

[0073] Secondly, please refer to Figure 2 and Figure 3 This application also provides a communication device, including: a host computer having a motherboard; and a light engine structure as described in the above embodiments, the light engine structure being connected to the motherboard.

[0074] The substrate has a connection end, and the light engine structure also includes a connection seat. The connection seat has a mounting groove, the substrate is housed in the mounting groove, and the connection end is electrically connected to the connection seat. The light engine structure is connected to an external motherboard through the connection seat.

[0075] In some embodiments, the inner wall shape of the mounting groove can be adapted to the outer contour of the substrate, serving as a limit and guide to prevent displacement or loosening of the substrate under vibration generated by high-speed signal transmission. The connector, as an intermediate transition component, not only achieves mechanical fixation between the optical engine structure and the external motherboard but also undertakes the function of transitioning electrical signals. By embedding the substrate into the mounting groove, the path length of signal transmission from the optical engine structure to the external motherboard can be shortened, reducing signal reflection and attenuation, which is crucial for maintaining the integrity of high-speed optical communication signals.

[0076] In some embodiments, the connector may be made of engineering plastic or ceramic material with good insulation properties to isolate electromagnetic interference between adjacent channels; in other embodiments, a shielding layer or grounding structure may be integrated inside the connector to further improve noise immunity.

[0077] In some embodiments, the connector may be provided with electrical connection points, specifically through, for example, elastic contacts on the connector base, or by direct welding between the connector and the connector base. When elastic contacts are used for connection, the connector base may be provided with spring pins or cantilever beam contact pads, which abut against the pads on the substrate connector. This non-permanent connection method allows the optical engine structure to be disassembled and replaced without damaging the substrate, facilitating subsequent maintenance, upgrades, or troubleshooting. The compression of the elastic contacts can be adjusted within a certain range to ensure the stability of the contact pressure, thereby ensuring low contact resistance and high conductivity reliability. Optionally, the surface of the elastic contacts may be gold-plated or palladium-plated to prevent oxidation and adapt to the skin effect of high-frequency signals. In contrast, if a direct welding method is used, such as fusing the solder balls of the substrate connector to the pads in the connector base via reflow soldering, lower parasitic inductance and a stronger mechanical bonding force can be obtained, suitable for applications with extremely high vibration tolerance requirements or where frequent plugging and unplugging is not required. However, welding is irreversible once completed. If the optical engine structure malfunctions, the entire connector may need to be replaced or complex repairs may be required. Therefore, the choice between flexible contact and welding fixation can be flexibly configured based on the actual usage environment, maintenance strategy, and cost considerations of the optical module.

[0078] In some embodiments, the connector has a positioning protrusion, and the positioning protrusion is at least partially located in the mounting groove. The substrate has a positioning groove, and the positioning protrusion engages with the positioning groove.

[0079] This positioning structure employs a "convex-concave" interlocking mechanical fit, where the shape of the positioning protrusion (such as cylindrical, square, or chamfered prism) precisely matches the inner cavity shape of the positioning groove. When the substrate is placed in the mounting groove, the operator or automated equipment simply aligns the positioning protrusion with the positioning groove and inserts it, using physical positioning to quickly determine the unique and correct position of the substrate within the mounting groove. This design not only restricts the substrate's translational freedom in the horizontal plane, preventing lateral or forward / backward displacement, but also limits the substrate's rotation around the vertical axis to a certain extent, ensuring precise alignment between the electrical connection points on the substrate and the elastic contacts or pads on the connector.

[0080] By designing a positioning protrusion that engages with a positioning groove, the substrate can be positioned during installation, significantly reducing reliance on the visual alignment accuracy of the assembly equipment and improving production assembly efficiency and yield. During the operation of the optical engine structure, this tight snap-fit ​​effectively resists minor displacements caused by external vibrations or thermal expansion and contraction, maintaining the stability of the electrical connection and preventing signal interruptions or increased bit error rates due to poor contact. Furthermore, the positioning protrusion can be designed with a foolproof structure (e.g., using an asymmetrical layout or a specific angled cut edge). If the substrate is placed in the wrong orientation or is of the wrong type, it will not be able to be fully embedded in the mounting groove, thus physically eliminating the risk of incorrect installation and protecting the expensive optical engine structure and substrate from damage. In some high-reliability embodiments, a small amount of thermally conductive adhesive or fixing adhesive can be filled between the positioning protrusion and the positioning groove to further enhance the heat dissipation path or mechanical locking force while achieving precise positioning.

[0081] In some embodiments, the connector can be detachably connected to the motherboard.

[0082] This modular design integrates the substrate, optical engine structure, and connector into a single, independent optical engine structure. During system assembly, this integrated module can be quickly installed onto the motherboard at a designated location, like a plug-in, eliminating the need for complex micro-assembly or soldering operations on the motherboard. This significantly simplifies the production line process and shortens the manufacturing cycle. More importantly, this discrete architecture greatly facilitates later maintenance: when a channel in the optical engine structure fails or requires a bandwidth upgrade, technicians simply need to remove the module from the motherboard and replace it with a new one, without needing to rework or scrap the motherboard. This significantly reduces system maintenance costs and improves equipment availability.

[0083] Specifically, the motherboard has an interface section, and the connector can be detachably connected to the motherboard and electrically connected to the interface section to form a near-packaged optical NPO architecture. The interface section is configured to be close to the switching chip on the motherboard so that the electrical connection path length between the optical engine structure and the switching chip is less than a preset threshold.

[0084] The preset threshold can range from 5mm to 50mm, with specific intermediate values ​​being 10mm, 20mm, or 30mm. The interface section is located on the motherboard within a fan-shaped area with a radius of 50mm around the switching chip. Preferably, the interface section and the switching chip are directly connected through multi-layer blind vias inside the motherboard, avoiding long-distance traces through the backplane or intermediate adapter board.

[0085] In traditional NPOs, optical modules are typically fixed directly to the motherboard via methods such as soldering. While this permanent connection method offers low contact resistance and good high-frequency characteristics, if the laser or detector in the optical engine structure fails, maintenance requires removing the entire module from the motherboard using a hot air gun or reflow soldering equipment. The high temperatures generated during this process can easily damage other precision components on the motherboard, and the solder pads are difficult to clean after removal, often necessitating the replacement of the entire motherboard, resulting in high maintenance costs and long maintenance cycles. In contrast, the optical engine structure in this embodiment features a detachable connector to the motherboard, facilitating replacement. The connector and interface section utilize a board-to-board connector, spring-loaded contacts, or edge-locking mechanism for mechanical locking and electrical conduction. When maintenance is required, operators simply need to unlock the mechanical latch of the connector or loosen the fixing screws to pull the optical engine structure perpendicular to the motherboard. This eliminates the need for heating or damaging the motherboard's circuitry. After replacing the module, it can be reinserted to complete the repair, significantly improving the maintainability and availability of the data center system.

[0086] Specifically, the contacts of the connector are set to contact and conduct with the interface section. The interface section is correspondingly set as gold finger pads or elastic contact pads on the printed circuit board, and its width matches the contact spacing of the connector. During assembly, when the connector is inserted into the interface section, the contacts undergo elastic deformation to generate positive pressure, which ensures the reliability of the electrical connection, prevents instantaneous circuit breakage due to vibration, and avoids excessive pressure that could cause plastic deformation or premature wear of the contacts.

[0087] After high-speed electrical signals are emitted from the switching chip, they are directly transmitted to the interface section via short traces inside the motherboard, and then directly to the drive circuit of the optical engine structure through the contacts of the connector, without any intermediate cable adapters or connectors. This direct-connect architecture eliminates the signal attenuation and reflection problems caused by long-distance copper cables or printed circuit board traces between the motherboard and the front panel in traditional pluggable optical module solutions.

[0088] Specifically, the connector is connected to the motherboard via a detachable structure. The detachable structure includes a positioning hole and a positioning part. The positioning hole and the positioning part are detachably connected. Either the positioning hole or the positioning part is located on the connector, and the other positioning hole or the positioning part is located on the motherboard.

[0089] The positioning holes and positioning parts work together to form a high-precision mechanical guiding system. During installation, the positioning parts (such as cylindrical pins, tapered pins, or chamfered protrusions) are first inserted into the positioning holes. The interference fit or clearance fit between the two guides the connector to its accurate placement, ensuring precise alignment between the optical engine structure and the electrical interfaces on the motherboard (such as gold finger sockets or board-to-board connectors), preventing pin bending or poor contact due to misalignment. This positioning method not only restricts the module's horizontal freedom but also withstands a certain amount of shear force, preventing the module from loosening during device operation vibrations. Depending on design requirements, the positioning holes can be located on the bottom or side of the connector, while the positioning parts are correspondingly located on the motherboard, and vice versa. This flexible layout allows engineers to optimize the structural design based on the motherboard's space constraints and wiring configuration.

[0090] In other embodiments, the connector and the motherboard can also be combined using detachable connection methods such as screw fixing or plug-in connection. If screw fixing is used, through holes can be made on the flange edge or specific mounting ears of the connector, and screws can be used to lock it onto the threaded post or nut seat of the motherboard. This method provides the strongest mechanical bonding force and excellent shock resistance, making it particularly suitable for high-vibration environments such as automotive and aerospace applications. However, it requires tools for disassembly and assembly, and is relatively slow. If plug-in connection (such as board-to-board connectors or edge slot connectors) is used, true "tool-free" hot-swapping functionality can be achieved: the bottom of the connector integrates a male connector, which can be directly inserted into the female connector on the motherboard, or a flexible snap-fit ​​structure can be used to lock the module into the motherboard slot. Although the mechanical strength of plug-in connection is slightly lower than screw fixing, its extreme convenience makes it the preferred solution for scenarios requiring frequent hardware replacement, such as data center servers and switches. Furthermore, multiple methods can be combined for hybrid fixing, such as initial alignment using positioning holes and positioning parts, followed by final locking with screws or snap-fits, to balance installation accuracy, connection reliability, and maintenance convenience.

[0091] In some embodiments, the connector is provided with first elastic contacts, through which the connector is electrically connected to the connection end. These first elastic contacts typically employ spring pins, cantilever beam springs, or crown spring structures, and are installed on the inner wall or bottom of the mounting groove of the connector, forming pressure contact with the solder pads or conductive contacts on the substrate connection end. When the substrate is inserted into the mounting groove, the first elastic contacts are compressed to generate a preload, ensuring stable electrical conduction under the low contact resistance required for high-speed signal transmission. The greatest advantage of this non-permanent connection method is its ease of disassembly and assembly: when maintaining or replacing the optical engine structure, there is no need to use a soldering iron for desoldering, avoiding thermal shock and potential damage to the precision optical engine structure on the substrate caused by high temperatures. It also eliminates the risk of solder pad detachment due to repeated soldering, greatly improving the maintainability and service life of the module.

[0092] In this embodiment, electrical connection between the first elastic contact and the substrate is achieved simply by contacting the first elastic contact at the connection end. This facilitates easy assembly and disassembly, allowing for fully automated assembly of the substrate and connector, and providing some tolerance for positional tolerances. The deformation stroke of the elastic contact can compensate for minor deviations in substrate thickness or mounting position, ensuring reliable contact. Furthermore, for high-speed signal transmission, the design of the first elastic contact typically considers impedance matching. By controlling the contact's length, diameter, and the surrounding dielectric environment, parasitic inductance and capacitance are minimized, thereby reducing signal reflection and insertion loss, and ensuring the integrity of 400G, 800G, and even higher speed signals.

[0093] Specifically, the connector is provided with a second elastic contact, and the connector is electrically connected to the motherboard through the second elastic contact.

[0094] The second flexible contact is typically located at the bottom or side interface of the connector, used for flexible crimping with the corresponding pads, gold fingers, or sockets on the motherboard. This design transforms the connection between the connector and the motherboard into a detachable, flexible contact mode, thus creating a fully solderless connection architecture from "motherboard-connector-substrate". When the entire optical engine structure needs to be replaced, simply release the mechanical locking (such as screws or clips) to directly remove the connector from the motherboard, and the second flexible contact will disconnect. The entire process is quick, clean, and requires no special tools.

[0095] This design facilitates the easy assembly and disassembly of the connector and motherboard, enabling true modular hot-swappable or cold-swappable functionality. In applications such as data centers or communication base stations, this design allows for the individual replacement of faulty optical modules without interrupting system power or disassembling other peripheral components, significantly reducing service interruption time. Simultaneously, the dual-ended elastic contacts (first and second elastic contacts) also serve as stress buffers: when the device is subjected to external vibration or impact, the elastic contacts can absorb some mechanical energy, preventing substrate breakage or solder joint cracking caused by rigid connections, further improving the operational reliability of the optical engine structure in harsh environments. To optimize high-frequency performance, the second elastic contact also undergoes impedance control and shielding to ensure continuous and stable transmission characteristics throughout the signal path from the motherboard to the optical engine structure.

[0096] Specifically, the connector can be an LGA socket. The use of an LGA socket leverages its high-density planar contact characteristics to accommodate the multi-channel signal transmission requirements of the optical engine structure. In this configuration, the connector integrates an array of flexible contact terminals that correspond one-to-one with the pad positions on the substrate connection end. These terminals are typically encapsulated within an insulating substrate, with only the contact surface exposed. When the substrate is inserted into the mounting slot and pressed firmly, the conductive pads on the bottom of the substrate form surface contact with the flexible terminals within the LGA socket, enabling conductive communication. This connection method avoids the risk of pins bending and breaking as with traditional pin-type connectors. Furthermore, because the LGA socket has no protruding pins, its overall height is lower, which helps reduce the space occupied by the optical engine structure on the motherboard and meets the strict vertical height limitations of rack-mounted equipment.

[0097] In some embodiments, the resilient terminals within the LGA socket can be designed as crown springs, cantilever beams, or hyperboloid structures to provide stable contact pressure and low contact resistance. For 400G, 800G, and even higher-speed optical communication signals, the LGA socket layout can optimize the arrangement of signal and ground pins, for example, by using staggered arrangements or surrounding the ground pins around high-speed signal pairs, to create a good return path and reduce crosstalk and electromagnetic radiation. Furthermore, as a standardized interface component, the LGA socket can be easily sourced from the supply chain, reducing the mold-making costs and manufacturing cycle of custom connectors. If different substrate sizes or pin definitions are required, only the corresponding LGA socket needs to be replaced without redesigning the entire connector's mechanical structure, facilitating the product series expansion of optical engine structures. In certain high-reliability applications, the LGA socket can also be equipped with locking latches or clamping mechanisms to apply additional clamping force after the substrate is installed, preventing momentary disconnection of contact due to equipment vibration and ensuring continuous signal transmission.

[0098] Furthermore, the light engine structure also includes a heat dissipation structure, which is connected to the substrate and thermally coupled to the light engine structure.

[0099] This heat dissipation structure can be made of materials with high thermal conductivity, such as oxygen-free copper, aluminum alloy, silicon carbide, or diamond composite materials. Its form can be designed as a vapor chamber, microchannel liquid cooling plate, or heat sink with dense fins, all closely attached to the chip surface. Since optical engine structures (especially high-speed laser chips and detector chips) generate significant heat during operation and are extremely sensitive to temperature (higher temperatures lead to wavelength drift, increased threshold current, and shortened lifespan), the heat dissipation structure directly covers or closely adheres to the heat-generating surface of the optical engine structure. This allows for the rapid conduction of Joule heat generated by the chip to the substrate with extremely low thermal resistance, and then conduction through the substrate to the connector or external environment, thereby controlling the chip junction temperature within a safe operating range.

[0100] Compared to traditional wire bonding solutions for chips, this solution improves the arrangement of the optical engine structure by allowing for additional heat dissipation structures to enhance its heat dissipation. In traditional flip-chip or wire bonding packages, chips are often encased in molding compound or limited by the space of the lead frame, making it difficult to directly mount an efficient external heat sink on top of the chip. This results in heat dissipation primarily through a single path via the bottom substrate, creating a significant heat dissipation bottleneck. However, the advanced integration architecture used in this embodiment (such as wafer-level bonding or Flip-Chip combined with TSV technology) fully exposes or makes the top surface of the optical engine structure easily accessible, breaking the space limitations of traditional packaging. This layout allows engineers to directly "tailor-make" a heat dissipation structure directly above the chip, creating a bidirectional three-dimensional heat dissipation channel: "chip top -> heat dissipation structure -> environment" and "chip bottom -> substrate -> environment." This bidirectional heat dissipation path significantly reduces overall thermal resistance and increases the heat dissipation power density per unit volume. This enables the optical engine structure to support stable operation at higher power consumption and higher speeds (such as 800G / 1.6T) within a smaller size, effectively solving the thermal management challenges brought about by high-density integration.

[0101] Furthermore, the thermal coupling interface between the heat dissipation structure and the light engine structure is typically filled with high-performance thermally conductive interface materials, such as thermally conductive gels, phase change materials, or indium foil, to fill the voids in the microscopic surface, eliminate the air insulation layer, and further improve heat transfer efficiency. In some high-end embodiments, the heat dissipation structure can also be integrated with the connector, utilizing the connector as a large heat sink, and even designing air ducts or water-cooling channels on its surface to achieve active heat dissipation, ensuring the performance consistency and long-term reliability of the light engine structure under long-term high-load operation.

[0102] Specifically, the heat dissipation structure includes a heat sink and a heat dissipation pad. The heat sink is at least partially attached to the substrate, and the heat dissipation pad is located on the side of the heat sink away from the substrate.

[0103] This layered composite structure ingeniously combines structural support and thermal management functions. The heat sink, serving as the core framework, has its bottom surface precisely machined to achieve a large-area, tight fit with the upper surface of the substrate. This fit not only establishes an efficient lateral heat diffusion path from the light engine structure through the substrate to the heat sink, utilizing the heat sink's large surface area to quickly and evenly distribute heat from localized hotspots, preventing heat accumulation beneath the chip; simultaneously, the heat sink acts like a "reinforcing rib" or "cover plate" covering the substrate, significantly improving the overall mechanical rigidity and bending resistance of the light engine structure. This effectively prevents warping and deformation problems common in large-size substrates or thinner designs, thus protecting the delicate internal micro-circuits and light engine structure from mechanical stress damage.

[0104] The placement of heat sinks in conjunction with the substrate facilitates heat dissipation from the light engine structure and enhances its overall strength. The heat dissipation pad, located on top of the heat sink (the side furthest from the substrate), is typically made of thermally conductive silicone, graphite sheets, or phase change materials with high compressibility resilience. Its primary function is to fill the minute gaps between the top of the heat sink and the outer casing, duct walls, or other heat dissipation components. Due to machining and assembly tolerances, it's difficult to achieve perfect flatness between the heat sink surface and the external contact surface. The heat dissipation pad eliminates these air gaps (air is a poor conductor of heat) through its own deformation, ensuring unimpeded heat transfer from the heat sink to the external environment. Furthermore, the soft heat dissipation pad also acts as a cushioning and shock absorber, absorbing external impacts and preventing damage to components caused by hard contact.

[0105] In one embodiment, the heat sink can be made of copper. Copper (especially oxygen-free copper) is chosen as the material for the heat sink due to its superior thermophysical properties: copper has a thermal conductivity of approximately 380-400 W / (m·K), far exceeding that of aluminum alloys (approximately 200 W / (m·K)) and other common structural materials. This means that copper heat sinks can conduct the high heat generated by the light engine structure to the entire module surface at an extremely fast speed, significantly reducing thermal resistance, making it particularly suitable for light engine structures with extremely high power density. Although copper has a higher density, increasing module weight, its excellent thermal conductivity and good ductility (facilitating the fabrication of complex bonding surfaces) make it the preferred choice for high-performance heat dissipation solutions. To balance weight and cost, other embodiments may also employ copper-aluminum composite materials (such as copper base and aluminum fins) or copper plating on aluminum surfaces to achieve the best balance between thermal conductivity and lightweight design. Furthermore, the surface of copper heat sinks is typically nickel-plated to prevent oxidation and improve interfacial adhesion with the heatsink.

[0106] In one embodiment, the heat dissipation structure has a connection hole, and the light engine structure also includes a coupling element that passes through the connection hole.

[0107] By incorporating a coupling element, the optical engine structure can emit or receive laser light. As a medium for optical signal transmission, the coupling element efficiently guides the high-speed modulated optical signal generated by the optical engine structure into an external fiber optic network, or precisely focuses externally input optical signals onto the photosensitive area of ​​the optical engine structure. During optical coupling, the lens structure or end-face shape within the coupling element can collimate, focus, or match the mode field of the beam to improve coupling efficiency and reduce insertion loss. Furthermore, the coupling element also provides isolation and protection, preventing damage to the chip from dust, moisture, or mechanical contact. Optionally, a transparent thermally conductive adhesive or cured UV adhesive can be filled between the coupling element and the connection hole, achieving both optical path sealing and heat transfer from the coupling element to the heat dissipation structure, thus improving local heat dissipation performance.

[0108] Specifically, the coupling element includes a connecting housing and an optical fiber, with the optical fiber located inside the connecting housing and the connecting housing passing through the connecting hole.

[0109] The connecting housing is typically made of metal, ceramic, or high-strength engineering plastic. Its outer diameter forms a clearance fit or interference fit with the inner diameter of the connecting hole, facilitating alignment during assembly and ensuring structural stability after assembly. The optical fiber is fixedly encapsulated within the central through-hole or pre-formed groove of the connecting housing, and its end is ground and polished to form a planar, spherical, or lens-shaped end face. In some embodiments, a microlens array or aspherical lens can also be integrated inside the connecting housing, with the end face of the optical fiber located near the focal plane of the lens. This lens system shapes the laser beam to accommodate external transmission fibers with different core diameters or numerical apertures. The design of the connecting housing passing through the connecting hole ensures that the stress point of the optical fiber is located outside the housing, preventing installation stress from being directly transferred to the fragile optical fiber and improving the reliability of the optical path connection.

[0110] The present invention also provides a communication device, which includes a host and an optical engine structure in any of the above embodiments; the host is provided with a motherboard; the optical engine structure is connected to the motherboard.

[0111] Specifically, the motherboard typically has connector slots or solder pads that match the optical engine structure. The optical engine structure achieves mechanical fixation and electrical connection with the motherboard through methods such as gold finger insertion, board-to-board connector crimping, or direct surface mount soldering. This connection method allows the optical engine structure to directly connect to the host's data exchange chip or network processor, establishing a high-speed data transmission and reception channel. In some embodiments, the motherboard also integrates power management circuitry and signal conditioning circuitry to provide a stable operating voltage for the optical engine structure and to perform impedance matching and noise filtering on input and output signals to ensure the stability of the communication link. The communication equipment can be network devices requiring high-bandwidth data exchange, such as data center switches, routers, servers, base station gateways, or optical transmission terminals. Their internal casings are typically designed with airflow channels or heat sinks to cooperate with the optical engine structure's own heat dissipation structure for system-level thermal management.

[0112] Furthermore, the light engine structure is detachably connected to the motherboard.

[0113] This detachable connection can be implemented by inserting the board edge gold fingers into a slot on the motherboard, or by using intermediate connectors such as board-to-board connectors or spring-loaded contacts to achieve electrical conductivity and mechanical fixation. In some embodiments, the housing of the optical engine structure may also be provided with a locking mechanism, such as a pull ring, a clip, or a screw fixing hole, which cooperates with the corresponding structure on the host chassis or motherboard to prevent accidental loosening of the device during vibration or handling. When maintenance is required, the operator only needs to release the locking mechanism and pull out the optical engine structure axially to separate it from the motherboard without using soldering tools or disassembling the internal structure of the entire communication device. Optionally, the connector interface on the motherboard can be designed to support hot-swapping, that is, while the communication device is powered on, the optical engine structure can be directly inserted or removed. The system can automatically identify the access or removal status of the module and perform corresponding configuration resets or link switching, thereby ensuring uninterrupted service operation.

[0114] The detachable connection between the optical engine structure and the motherboard facilitates the assembly and subsequent disassembly and maintenance of the optical engine structure. During assembly, the detachable design allows the optical engine structure to be produced and tested as an independent standard component, and then installed onto the motherboard after passing the test. This simplifies the overall assembly process of the host machine, reduces reliance on precision alignment equipment on the production line, and improves production efficiency and yield. If a defect is found in the optical engine structure during host assembly, a new module can be directly replaced without scrapping the entire motherboard or performing complex rework, effectively reducing manufacturing costs. In the later maintenance phase, when the optical engine structure reaches the end of its service life, experiences performance degradation, or suffers hardware failure, maintenance personnel can quickly locate and replace the faulty module, significantly shortening the mean time to repair (MTBL) and improving the availability of the communication equipment. Furthermore, with the iterative upgrades of optical communication technology, users can flexibly replace optical engine structures with different rates, transmission distances, or wavelengths according to actual needs without replacing the entire host machine or motherboard. This modular design gives the communication equipment excellent scalability and technical compatibility.

[0115] The present invention also provides a data center system, which includes a server rack and the communication equipment in any of the above embodiments, wherein the communication equipment is disposed in the server rack.

[0116] Specifically, the cabinet can accommodate multiple vertically arranged mounting positions, where communication equipment is secured via rails, trays, or brackets. The cabinet not only provides physical support and protection for the communication equipment but also creates a system-level cooling duct and fiber optic cabling management space. Fiber optic cable trays, cable management rings, and cable routing holes can be pre-installed on the cabinet's internal back panel or side walls. These cabling structures correspond to the fiber optic exit positions of the optical engine structure on the communication equipment, allowing couplers leading from the optical engine structure to directly and via a short path into the cabinet's cabling channels without requiring long-distance copper cable splicing within the cabinet.

[0117] Because the communication equipment adopts a near-package optical NPO architecture, the electrical connection path between the switching chip on the motherboard and the optical engine structure is limited to the board level. This means that high-frequency electrical signals do not need to be transmitted to the front panel of the rack and converted into optical signals through backplane connectors as in traditional architectures. Therefore, the space utilization inside the rack is significantly optimized in this data center system, eliminating a large amount of space occupation and reducing the risk of cable tangling and airflow resistance inside the rack. The airflow design of the rack can be optimized for the heat dissipation structure of the communication equipment. For example, air guides can be installed at the corresponding positions of the heat dissipation pads of the communication equipment, allowing cool air to flow directly over the surface of the heat sink. The negative pressure generated by the rack fan assembly quickly expels heat from the rack, thereby supporting the deployment of equipment with higher power density.

[0118] In some embodiments, a data center system may include multiple racks arranged side-by-side, with communication devices within each rack interconnected via a main fiber optic patch panel at the top or bottom of the rack. Because individual communication devices integrate high-density NPO optical interfaces, the entire data center system can achieve a greater level of data exchange capacity within a limited footprint. This NPO-based data center system effectively addresses the bottlenecks in energy consumption, heat dissipation, and signal integrity faced by hyperscale data centers by placing the optical engine structure as close as possible to the switching chip and combining rack-level optical cabling optimization.

[0119] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0120] The above-described embodiments are merely illustrative of several implementation methods of the embodiments of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the embodiments of this application, and these all fall within the protection scope of the embodiments of this application. Therefore, the protection scope of the patent for the embodiments of this application should be determined by the appended claims.

Claims

1. A light engine structure, characterized in that, include: A driver chip, comprising a driver circuit and a welding electrode, is used to connect to a substrate or PCB board via gold wire bonding. A flip-chip VCSEL with a lens structure is soldered to the soldering electrode of the driver chip and electrically connected to the driver circuit. The flip-chip VCSEL with lens structure includes a VCSEL chip and a lens structure integrated on the substrate of the VCSEL chip; the lens structure is located in the light emission path of the VCSEL chip and is used to collimate or focus the light emitted by the VCSEL chip.

2. The light engine structure according to claim 1, characterized in that, The lens structure is one of a convex lens, a microlens, or a Fresnel lens, and the lens structure is integrally formed with the substrate or formed on the surface of the substrate through an additional process.

3. The light engine structure according to claim 2, characterized in that, The lens structure is a concave convex lens. The concave convex lens forms a concave structure on the substrate surface through an etching process, and the concave structure has the optical effect of a convex lens.

4. The light engine structure according to claim 3, characterized in that, The substrate thickness of the concave convex lens ranges from 0.15 to 0.4, the radius of curvature ranges from -0.08 to -0.2, and the conic coefficient ranges from -0.4 to -1.

5.

5. The light engine structure according to claim 1, characterized in that, The optical axis of the lens structure is aligned with the center of the light-emitting area of ​​the VCSEL chip.

6. The light engine structure according to claim 1, characterized in that, The optical engine structure also includes an optical fiber, the light input end of which is coupled to the light output side of the flip-chip VCSEL with lens structure, for receiving the optical signal processed by the lens structure.

7. The light engine structure according to claim 6, characterized in that, The optical fiber is aligned and coupled to the flip-chip VCSEL containing the lens structure either through an optical fiber connector or directly.

8. The light engine structure according to claim 1, characterized in that, The driver chip also includes a control circuit, which is used to control the drive current and operating state of the flip-chip VCSEL with lens structure.

9. A communication device, characterized in that, include: The host computer is equipped with a motherboard; as well as, The light engine structure as described in any one of claims 1-8, wherein the light engine structure is connected to the motherboard.

10. The communication device according to claim 9, characterized in that, The light engine structure is detachably connected to the motherboard.

11. A data center system, characterized in that, include: Server racks; and, The communication device as described in claim 9 or 10, wherein the communication device is disposed in the cabinet.

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