Characterization and Applications of Vector Phase-Sensitive Amplifiers

Licentiatavhandling, 2015

This work is devoted to the characterization of vector phase-sensitive amplifiers and processors. A detailed analysis of degenerate vector phase-sensitive amplifier (PSA) is performed. The gain and phase-sensitive extinction ratio are theoretically analyzed using three-wave theory. Experiments and simulation results confirm the validity of this three-wave theory. The influence of polarization-mode dispersion is also evaluated, showing that aligning the pump polarizations at the fiber input is essential in order to achieve the theoretically predicted results. The scheme is also compared to the degenerate scalar PSA scheme. At the same pump power, the vector PSA has lower gain but also less influence from higher-order idlers and lower pump depletion due to FWM between the pumps. Using the degenerate vector PSA, phase-sensitive (PS) amplification of dual-polarization (DP) binary phase-shift keying (BPSK) signals was demonstrated. To the best of our knowledge, this was the first demonstration of a DP-modulated signal with large net phase-sensitive gain. Furthermore, we also demonstrated that this scheme can phase regenerate the signal. The same scheme was also used for a different purpose: quadrature decomposition into two cross-polarized waves. We demonstrated demultiplexing of quadrature phase-shift keying (QPSK) signal into two cross-polarized BPSK signals by the operating the amplifier in phase-insensitive mode. The design of a novel phase-locked loop scheme enabled stable operation and negligible penalty in the decomposition.