Low-Parametric-Crosstalk Phase-Sensitive Amplifier for Guard-Band-Less DWDM Signal Using PPLN Waveguides

We demonstrated guard-band-less dense wavelength division multiplex signal amplification with a phase sensitive amplifier (PSA). The PSA consists of periodically poled lithium niobate waveguide that employs two-stage nonlinear process, namely second-harmonic generation and optical parametric amplification, which makes it possible to mitigate the crosstalk induced by the optical parametric interaction between DWDM channels. The PSA amplified 16-channel signals simultaneously with a gain of 17 dB over 12-nm wavelength range. We demonstrated a 2.5-dB signal-to-noise-ratio improvement and a low noise figure of 2.1 dB below the 3-dB quantum limit. We achieved the amplification of a 10-Gbaud quadrature phase shift keying signal with phase and amplitude regeneration.