HgCdTe APD detector module for deep space optical communications

Abstract

A 4-quadrant large area HgCdTe APD detector module have been developed and characterized in view of application in deep space optical communications. Single photon detection capacity has been demonstrated on each of the four channels of the detector module, associated with a bandwidth close to 400 MHz. The performance for pulse position modulation (ppm) has been estimated from the detection of strongly attenuated laser pulses and were found to be close to the system performance specifications given by ESA: the pulse detection probability in a time slot of 800 ps was measured to be higher about 90 % for a signal of 7 photons focused on the center on one channels, associated with a false alarm rate below 1 %, although the sensitivity of the full detector module was limited by a low quantum efficiency and a high dark count rate. With a 16-ary ppm modulation, this corresponds to a data rate of 320 Mbps at less than 2 photons per bit.