Ultra-low-power, long-wavelength photoreceivers for massively-parallel optical data links

An ultra-low-power, long-wavelength photoreceiver based on InGaAs-InP heterojunction bipolar transistors is reported. The photoreceivers were designed for massively parallel applications where low-power density is necessary for both electrical and thermal reasons. We demonstrate two-dimensional, four-by-four arrays of photoreceivers for free-space optical data links that interface directly with 3.3 V CMOS ASICs and dissipate less than 12 mW/channel; lower power is possible. Propagation delays of /spl sim/1 nsec were measured and large signal operation to 800 Mbits/sec is demonstrated. The array is on a 500 /spl mu/m pitch and can be easily scaled to much higher density. The photoreceivers can be utilized in both free-space and guided-wave applications.