Innovative Fan-Out Embedded Bridge Structure for Co-Packaged Optics

Datacenter, machine learning, and artificial intelligence applications are demanding bandwidth of mroe than 25.6Tb/s. However, achieving the high channel counts required to reach these speeds usnig the current approach of pluggable modules that insert into the faceplate of the rack switch is very challenging. However, in order to overcome these challenges and eliminate data transmission bottlenecks, CPO (Co-packaged optics) concept was proposed for the next generation packaging soluton to increase the data trasmission rate and bandwidth. CPO is an architecture to integrate the EIC (electrical integration die) and PIC (Photonics integration die) into a single packaging which shorten the optic and electrons signal transmission path and enhance the transition efficiency. In this study, we demonstrated FO-EB (Fan-Out Embedded Bridge) structure to integrate PIC and EIC dies into single package by embedded die technologies, FO-EB has shown the robust design to stack PIC and embedded EIC die vertically which PIC die was bonded on fan-out chip module with overhang design. However, in order to investigate the CPO electrical peroformance between the MPM-FCBGA and FO-EB structure, we built the simulation models in this analysis. As the result, comparing to the tranditional MPM FCBGA CPO design, the insertion loss and RC delay were improved dramatically in FO-EB CPO. In this paper, FO-EB structure for CPO solution is sucessfully demonstrated, PIC overhang design allows sufficient space to assemble optical fiber. Besides, EIC dies are embedded into fan-out module which shorten the signal transimission distance between PIC and EIC die, it achieves the goals for both reducing CPO form factor and enhancing signal transition efficiency between optic and electronic die. Undoubtedly, the FO-EB structure will be the robust PIC and EIC vertical stacking solution for CPO design which brings high performance and small form factor benefits in silicon-photonics applications.