Signal Design and Detection in Presence of Nonlinear Phase Noise

Abstract

Abstract-In optical fiber transmission systems using inline amplifiers, the interaction of a signal and amplifier noise through the Kerr effect leads to nonlinear phase noise that can impair the detection of phase-modulated signals. We present analytical expressions for the maximum-likelihood (ML) decision boundaries and symbol-error rate (SER) for phase-shift keying and differential phase-shift keying systems with coherent and differentially coherent detection, respectively. The ML decision boundaries are in the form θ(r) = c 2 r 2 + c 1 r + c 0 , where θ and r are the phase and the amplitude of the received signal, respectively. Using the expressions for the SER, we show that the impact of phase error from carrier synchronization is small, particularly for transoceanic links. For modulation formats such as 16-quadrature amplitude modulation, we propose various transmitter and receiver phase rotation strategies such that the ML detection is well approximated by using straight-line decision boundaries. The problem of signal constellation design for optimal SER performance is also studied for a system with four signal points.Index Terms-Maximum likelihood (ML) detection, nonlinear optics, optical fiber communication, optical Kerr effect, phase noise, quadrature amplitude modulation (QAM).

An ML-Based Detector for Optical Communication in the Presence of Nonlinear Phase Noise

“…This effect is also apparent in the results from [9], but no explanation was given. This oscillatory behavior is caused by the signal power dependent nonlinear phase rotation in the received constellation.…”

“…A study on the performance degradation is presented in [8] for clock recovery in the presence of NLPN. In [9], ML decision boundaries are derived for an optical channel with nonlinear phase noise, only considering distributed amplification. In addition, mitigation for 16-QAM is inherently sub-optimal as it comprises two stages: ring discrimination followed by phase post-compensation.…”

Generation of 64-QAM Signals Using a Single Dual-Drive IQ Modulator Driven by 4-level and Binary Electrical Signals

“…Simulation results show that the driving signals chosen in our experiments will induce a < 1 dB penalty compared with the standard square 64-QAM constellation. Alternatively, optimal decision boundaries based on maximum likelihood or other metrics can be used to improve detection performance [9][10]. In this case, the driving amplitude requirements for 64-QAM signal generation can be graphically represented in Fig.…”

Joint Iterative Carrier Synchronization and Signal Detection for Dual Carrier 448 Gb/s PDM 16-QAM

“…It has been shown that carrier phase and frequency recovery can be performed by various techniques: digital phase-locked loop (PLL), Viterbi-Viterbi, blind-phase-search, decision aided Maximum Likelihood (ML) estimation etc, and references therein [3][4][5][6] . Furthermore, it has been demonstrated that by employing ML signal detection, different linear and nonlinear signal impairments can be mitigated [7][8] .…”