A 2.5-mW SOS CMOS optical receiver for chip-to-chip interconnect

This paper reports on the design of a differential optical receiver in silicon-on-sapphire (SOS) complementary metal-oxide-semiconductor (CMOS). The low-power characteristics (2.5 mW) and small footprint make it a good candidate for two-dimensional optoelectronic interchip interconnects where the transparency of the substrate facilitates system integration and packaging. A differential transimpedance amplifier (TIA) with positive feedback at the front end extends the bandwidth of traditional differential TIAs when the capacitance of the photodetector is smaller than the capacitance of the gates in the differential pair. The full receiver tested in the 0.5-μm ultrathin silicon (UTSi) SOS-CMOS Peregrine process consumes 2.5 mW when operated at or near gigabit rates, with bit-error rates of better than 10^-12 taken at 750 Mb/s.