Polarization-Insensitive Fiber Optical Parametric Amplifier with Noise Figure down to 4.4 dB enabled by Mach-Zehnder Architecture

Abstract

We demonstrate a Mach-Zehnder (MZ) architecture for polarization-insensitive (PI) fiber optical parametric amplifiers (FOPA) and confirm that it improves both noise figure and nonlinear crosstalk as compared to PI-FOPAs employing a polarization diversity loop. We characterize the MZ PI-FOPA by employing it to amplify 17x100 GHz-spaced WDM channels including a 35 GBaud PDM-QPSK signal between 1528.0 and 1540.56 nm with a net gain between 15.5 and 24 dB. We demonstrate the record low PI-FOPA noise figure down to 4.4 dB, and a noise figure below 6 dB across all amplified channels for the total signal output power up to 13 dBm. The latter demonstrates an improvement in the nonlinear crosstalk tolerance by $\sim$7 dB as compared to previously reported looped PI-FOPAs.