Non-data Aided Timing Phase Recovery Scheme for Digital Equalization of Chromatic Dispersion and Polarization Mode Dispersion

Abstract

In this paper we propose an electronic domain timing phase selection scheme for the optical communication systems suffering from inter-symbol-interference (ISI) distortion due to chromatic dispersion (CD) or polarization mode dispersion (PMD). In the presence of CD/PMD a proper timing phase selection is important for discrete time domain equalizers, since different timing phases produce different nonlinear ISI channels of different severity. The proposed timing phase recovery scheme based on dispersion minimization (DM) practically approximates the optimal minimum mean squared error (MMSE) timing phase without training signals which reduces overall throughput substantially, especially in time-varying channels such as PMD. The simulation results show that the proposed DM timing agrees with MMSE timing phase, under proper normalization of the received signals, for various dispersion and OSNR.

Robust Architecture for Autonomous Coherent Optical Receivers

“…This is a feature of timing recovery and not of the blind processing module of the architecture. To overcome this challenge, other works have proposed solutions leading to robust digital clock recovery algorithms such as the methods described in [14][15][16]. Note that the recovered timing phase error is arbitrary since polarizations are still scrambled at this point in the architecture.…”

A Feedforward Partial Phase Noise Mitigation in the Time-Domain using Cyclic Prefix for CO-OFDM Systems

“…At the receiver, assuming perfect synchronization under proper distortion monitoring such as in [12,13], the first  samples,     ⋯    , i.e., those corresponding to the CP, are removed and processed using a DFT. The output   , which corresponds to the source QAM symbol   , is given as…”