Noise and error rate performance of semiconductor laser amplifiers in PCM-IM optical transmission systems

TLDR

The study theoretically investigates the use of semiconductor laser amplifiers in intensity‑modulated digital optical transmission systems. The authors model an optical linear amplifier repeater placed between electronically regenerating terminal repeaters and a preamplifier before the photodetector, consider traveling‑wave and Fabry‑Perot laser amplifiers, and evaluate noise and error‑rate performance using photon‑master‑equation‑based mean and variance calculations to obtain worst‑case output‑voltage variance. They show that adding a preamplifier reduces the required receiving power for direct detection, and that an optical linear amplifier repeater can extend the spacing between electronically regenerating terminals.

Abstract

Applications of semiconductor laser amplifiers in intensity modulated digital optical transmission systems were studied theoretically. An optical linear amplifier repeater between electronically regenerating terminal repeaters and an optical linear preamplifier in front of a photodetector in an electronically regenerating repeater are discussed. Both traveling-wave type and Fabry-Perot cavity type laser amplifiers are considered. The noise and error rate performance in these systems are evaluated using formulations for semiconductor laser amplifiers. The mean and variance in the optical amplifier output photons calculated by the photon master equation [1] is used to obtain the worst case variance in the equalized output voltage [2] for these systems. The required receiving power reduction from direct detection scheme by a preamplifier system and the repeater spacing expansion between two electronically regenerating terminals by an optical linear amplifier repeater system are delineated.