112-Gb/s PAM4 transmission using polymer-waveguide-coupled silicon-photonics for next-generation co-packaged optics

A technology of co-packaged optics, which is mounting photonics integrated circuits and electronic integrated circuits on the same board, is essential to meet the demands of high-capacity transmission in data centers. In this respect, polymer optical waveguides have attracted much attention because of mechanical stability, excellent processability, and compatibility with electronic circuits. To achieve high-capacity optical transmission, we are developing a new package substrate, which we call active optical package (AOP) substrate, as a solution of co-packaged optics. The AOP substrate consists of a conventional organic package substrate such as glass-epoxy substrates, on which silicon photonics dies are embedded and SMF connectors are mounted. In the AOP, the silicon photonics inputs/outputs (I/Os) and the optical connectors are connected by 3D optical wiring technology that has a function of converting the pitch size. The 3D optical wiring is realized with a pair of micro-mirrors and a single-mode polymer waveguide. First, we have evaluated the high-speed optical transmission performance of a single-mode polymer optical waveguide for LAN-WDM network. We observed there was no noticeable penalty for optical transmission for all LAN-WDM channels. And then, we demonstrate transmission of an AOP substrate comprising of silicon waveguide, two micro-mirrors and polymer waveguide. Transmission of 112-Gb/s PAM4 optical signal was performed without noticeable penalty up to 85 degrees C.

Automated summary

Co-packaged optics technology is essential for high-capacity transmission in data centers. Polymer optical waveguides have attracted attention due to their mechanical stability, processability, and compatibility with electronic circuits. Developing an active optical package (AOP) substrate, which includes silicon photonics dies and SMF connectors on a conventional organic package substrate, allows for 3D optical wiring and high-capacity optical transmission.