Optical Preamplifier Receivers: Application to Long-Haul Digital Transmission

Abstract We review the progress and technical issues of optical preamplifier receivers for high-speed long-haul digital transmission applications. We treat the optical preamplifier detection from an engineering standpoint (instead of the fundamental physics viewpoint) by emphasizing, theoretically and experimentally, how to determine the preamplifier receiver parameters for optimum performance. We also compare the avalanche photodetector and coherent receiver to the optical preamplifier receiver and show that the optical preamplifier receiver offers superior receiver sensitivity above 2.5 Gb/s data rate. Based on the results with experimental prototype receivers and a theoretical model, we conclude that the realistically achievable receiver sensitivity for a practical two-stage, 980-nm-pumped preamplifier receiver is ∼130 photons/bit independent of data rate (i.e., -44, -41, and -38 dBm for 2.5, 5, and 10 Gb/s, respectively).