【摘要】 文中针对高速光互连应用需求，研制了基于玻璃波导基板的集成垂直腔面发射激光器阵列的高速光电共封装光路板。该光路板中，激光器芯片以出光面向下的方式倒装焊于玻璃基板上表面，光信号经反射面转向后耦合进入玻璃波导传输，最终与光纤阵列完成耦合。高速驱动芯片也采用倒装焊工艺集成于同一块玻璃基板，实现光电芯片的高密度共封装集成。电磁仿真结果表明，50 GHz频率下，文中采用的倒装焊结构的单点衰减较等长引线键合结构降低约0.5 dB。实验结果表明，该光路板的链路在850 nm波长下插入损耗为1.7 dB，实现了单通道112 Gb/s的高速信号互连。该研究可突破传统引线键合封装在带宽与集成密度方面的瓶颈，为100 Gb/s及以上速率的高速光互连系统提供可行的技术方案。更多还原

【Abstract】 Objective Compared with traditional organic substrates, glass substrates feature higher RF bandwidth, better temperature stability, lower CTE, and superior warpage control, making them the preferred choice for highprecision and high-density optical circuit boards. Conventional top-emitting wire bonding schemes suffer from inherent bottlenecks, including the large footprint of top fiber coupling structures, restricted integration density and bandwidth, and high insertion loss. The bottom-emitting VCSEL flip-chip scheme adopted in this work can effectively address the above limitations while reserving chip heat dissipation space, making it suitable for optical interconnection applications beyond 100 Gb/s. Given the lack of mature high-speed optoelectronic co-packaged OCBs with the above advantages, this work designs and fabricates an optoelectronic co-packaged OCB based on glass waveguides through flip-chip bonding technology. This work integrates VCSEL arrays, glass waveguides and high-speed driver chips to realize large-bandwidth and high-density optical interconnection, and provides a feasible solution for board-level high-speed optical interconnection at 100 Gb/s and beyond.Methods Glass waveguide preparation was completed through pretreatment cleaning, electron beam evaporation deposition of a mask film, ultraviolet lithography, pattern transfer, as well as two sequential rounds of ion exchange featuring thermally driven processing and electric field-assisted processing in turn, followed by final cleaning. Guided by the positioning reference of the glass waveguide substrate, copper circuit preparation and unit division were completed by means of lithography, copper layer deposition, electroplating, electroless nickelpalladium-gold plating, stripping, flash etching, and dicing procedures. Solder balls were placed on the pads prior to flip-chip bonding of the driver chip and VCSEL array. Wire bonding technology was adopted to connect the PCB and integrate the entire assembly with the test platform. Power was supplied via the I2C protocol. The relative positions of the waveguides and FAs were calibrated and fixed by curing to achieve final optical coupling.Results and Discussions The buried waveguide is quasi-circular, with a core refractive index of 1.52 and a substrate refractive index of 1.50, as well as an insertion loss of approximately 0.4 dB. It can be efficiently coupled with VCSELs and optical fiber arrays, satisfying the requirements of low-loss interconnection. At50 GHz, the single-point insertion loss of 300 μm flip-chip bonding is 0.5 dB lower than that of wire bonding of the same length. The total insertion loss from the VCSEL to the fiber array is 1.7 dB. The 3 dB bandwidths of the driver and VCSEL are 40 GHz and 25 GHz, respectively. Reducing the wire bonding distance can effectively optimize link loss. A clear open eye diagram is obtained for 112 Gb/s PAM4 interconnection. For 106 Gb/s PAM4 transmission with a bit error rate below 10-6, the proposed optical circuit board exhibits obvious power advantages over the fully wire-bonded packaging scheme. Meanwhile, it supports single-lane 112 Gb/s signal transmission, which satisfies the demands of high-speed optical interconnection.Conclusions This study designs and fabricates a glass-based optical circuit board for co-packaged optics,utilizing glass waveguides and the flip-chip bonding process. The fabricated device exhibits an overall insertion loss of 1.7 dB at 850 nm, and achieves single-lane 112 Gb/s signal transmission, offering a feasible solution for board-level high-speed optical interconnection. Future work will focus on structural optimization to improve process tolerance, high-bandwidth device integration with thermal management for higher transmission speeds,and multi-channel design toward large-scale, high-density glass-based integrated optical systems.更多还原