Ultra-low-noise, Broadband Phase-Sensitive Optical Amplifiers and Their Applications

Frequency non-degenerate phase-sensitive amplifiers (PSAs) have the potential to realize broadband and noiseless amplification. However the rigorous requirement of phase- and wavelength-locking of the input waves has significantly hampered their progress. In this paper, we review recent research on this type of optical amplifier. This work is based on a copier-PSA scheme, which consists of a parametric phase-insensitive copier followed by one or more PSAs. Broadband gain and noise performance of a fiber-based non-degenerate PSA has been characterized, both theoretically and experimentally. A record-low 1.1 dB noise figure was measured at > 26 dB gain, and a clear phase dependent gain was observed. Moreover, potential applications including phase noise squeezing and ultra-low noise, multi-channel and modulation-format-transparent linear amplification with up to 6 dB link noise figure advantage over conventional EDFA-amplified links have been experimentally demonstrated. The prospects and practical challenges of this intriguing amplification technology are also discusse