Miniaturized bidirectional optical subassembly using silicon optical bench with 45-deg micro-reflectors in short-reach 40-Gbit/s optical interconnects

The development of a 4-channel x 10-Gbits/s optical interconnect module based on a silicon optical bench (SiOB) is presented. The 4-channel vertical-cavity surface-emitting laser (VCSEL) and photo diode (PD) arrays are flip-chip assembled onto the pedestals of SiOB using Au/Sn solder bumps to form an SiOB-based bi-directional optical subassembly (BOSA) configuration. The optical coupling of VCSEL-to-multi-mode fiber (MMF) and MMF-to-PD without adding coupled optics is -5.2 and -2 dB, respectively. The wide alignment tolerances of 1-dB power variation for the transmitting and receiver parts to be ±15 μm are achieved. The clearly open 10-Gbits/s eye patterns of transmitting part as well as the 10^-12-order bit error rate (BER) at the receiving part verify the proposed SiOB-based module is suitable for the application of 4-channel x 10-Gbits/s optical interconnects.