Signal Amplification and Photorefractive Phase Conjugation for Space Laser Communications

摘要

Photorefractive phase conjugation is attractive for applying in future laser communications terminals due to its incorporated tracking and wave front distortion compensation capabilities. But due to the comparatively high required optical power, it is generally unpractical to employ components based on the photorefractive effect into a space laser communications system.This paper follows the approach to overcome this problem by using a semiconductor optical amplifier (SOA). Since the amplified spontaneous emission noise arising in the amplification process has an erasing effect on the diffraction gratings in the photorefractive medium, it also affects the creation of phase conjugation. Therefore, the performance of photorefractive phase conjugation and two-wave-mixing depending on the noise power is examined and the minimum SOA-input power to successfully perform photorefractive experiments is determined experimentally by using a Rh:BaTiO_3 photorefractive crystal.