Kwansik Cho

Si-based optical I/O for optical memory interface

Optical interconnects may provide solutions to the capacity-bandwidth trade-off of recent memory interface systems. For cost-effective optical memory interfaces, Samsung Electronics has been developing silicon photonics platforms on memory-compatible bulk-Si 300-mm wafers. The waveguide of 0.6 dB/mm propagation loss, vertical grating coupler of 2.7 dB coupling loss, modulator of 10 Gbps speed, and Ge/Si photodiode of 12.5 Gbps bandwidth have been achieved on the bulk-Si platform. 2x6.4 Gbps electrical driver circuits have been also fabricated using a CMOS process.

10 Gb/s, 1×4 optical link for DRAM interconnect

We present a 10-Gb/s, 1×4 optical link based on a DRAM-integration-ready bulk-silicon modulator for multi-drop CPU-DRAM interconnects. The bulk-silicon modulator operated at 10 Gb/s on a die, and at 5 Gb/s in a QFP package. The 1×4 optical link was limited not by signal integrity but by optical power budget, demonstrating its scalable capacity for the future multi-drop memory bus.