Phase-Sensitive Parametric Signal Processing in Optical Communications

Doktorsavhandling, 2016

This thesis covers the analysis of several schemes for parametric processing in fiberoptic communication systems, focusing mainly on phase-sensitive processing. Vector phase-sensitive amplifiers are characterized and phase regeneration of a dualpolarization (DP)-binary phase-shift keying signal (BPSK) signal is experimentally demonstrated. Theoretically, the requirements for achieving polarization-independent phase-sensitive amplification of both single and dual polarization signals in a general scenario are also analyzed in this work. This part of the thesis is concluded by experimentally demonstrating mitigation of fiber nonlinearities in an installed link by performing mid-span spectral inversion with a vector parametric amplifier. This thesis also covers the analysis of polarization-assisted phase-sensitive processors to achieve quadrature decomposition. Using a vector amplifier, decomposition of a quadrature phase-shift keying (QPSK) signal into two BPSK signals is experimentally demonstrated. A polarization-assisted phase-sensitive processor based on a polarization-diverse implementation is used for achieving quadrature decomposition of a 16 quadrature-amplitude modulation (16-QAM) into two 4 pulse-amplitude modulation (4-PAM) signals . The final part of this thesis proposes and demonstrates the concept of selfhomodyne superchannel by comb regeneration. By transmitting two unmodulated carriers, self-homodyne detection of 24×DP-32-QAM signals is demonstrated by alloptical comb regeneration based on Brillouin amplification and a parametric comb in a proof-of-principle experiment. Compared to conventional self-homodyne schemes, comb regeneration reduces the complexity and limits the spectral overhead in selfhomodyne receivers.