Noise analysis of LWIR photodetector based on HgCdTe for free space optical receiver

Abstract

In present paper we have reported low noise LWIR photodetector optical receiver used in intensity modulated (1M/ DD) direct detection system for free space optical communication applications. The model is used to explore the different types of noises associated with the photodetector as well as of amplifier and biasing resisters. In dark current modeling of detector we have considered all possible recombination mechanisms e.g. fundamental recombination (hand-to-band and Auger) and nonfundamental recombination (Shockley-Read-Hall and Surface recombination) mechanisms. All the noise components of the receiver circuit have been analyzed theoretically. The present analysis leading to dark current of the photodetector is I D = 5X 10 -7 A, dynamic resistance of the LWIR detector R D = 10 7 ω, and noiseequivalent- power of receiver circuit NEP = 10 -14 W-Hz 1/2.