CMOS photodetectors for correlation peak location

The design and operation of CMOS photodetectors for locating correlation peaks in an optical processor are discussed. The detectors, which are fabricated in silicon CMOS, employ analog position sensing and on-chip circuitry to sequentially find intensity peaks. Two test devices are described: a two element competitive array with 400 μm×180 μm 1-D sensors and a 400 μm×400 μm 2-D sensor. The 2-D sensor resolves beam displacements of 0.25 μm and the two-element competitive array demonstrates combined circuit and photodetector response times down to 20 μs.