A. quad 2.7 Gb/s parallel optical transceiver

The realization of short-reach parallel optical interconnects based on multi-mode fiber ribbons requires the coalescence of vertical-cavity surface-emitting lasers, photodetectors, transmit and receiver circuitry, and an optical power control system within a compact assembly. This paper describes a solution based on silicon-on-sapphire IC technology and demonstrates an optical transceiver featuring four transmitters and four receivers, each operating at up to 2.7 Gb/s. Flip-chip bonding is used to attach four-element laser and photodetector die to the IC. Optical signals propagate through the transparent sapphire substrate. Lateral photodiodes implemented in the IC process are used to monitor the optical output power, and embedded controllers have been developed to regulate this power on a per-channel basis. Key circuit designs are presented, following a summary of the optoelectronic chip-scale packaging technology.