Phase-squeezing properties of non-degenerate PSAs using PPLN waveguides

摘要

We investigate the phase squeezing characteristics of non-degenerate phase-sensitive-amplifiers (PSA) based on periodically-poled-lithium-niobate (PPLN) waveguides. We implement two PSA configurations with phase insensitive idler generation performed in both highly-non-linear-fiber (HNLF) and PPLN waveguides. In both cases we demonstrate regeneration of a noisy BPSK signal, despite net signal attenuation in the phase sensitive PPLN, and show that the level of phase squeezing varies with the phase sensitive dynamic range (PSDR). We observe that weak idler generation in the PPLN limits the achievable PSDR and that use of HNLF for idler generation leads to the largest PSDR. However, in phase regeneration measurements, we observe that significant amplitude noise, increasing with the PSDR, is added to the signal, originating from pump phase modulation required to overcome stimulated Brillouin scattering.