Adaptive Electronic Dispersion Compensator for Chromatic and Polarization-Mode Dispersions in Optical Communication Systems

Abstract

The widely-used LMS algorithm for coefficient updates in adaptive (feedforward/decision-feedback) equalizers is found to be suboptimal for ASE-dominant systems but various coefficient-dithering approaches suffer from slow adaptation rate without guarantee of convergence. In view of the non-Gaussian nature of optical noise after the square-law optoelectronic conversion, we propose to apply the higher-order least-mean 2Nth-order (LMN) algorithms resulting in OSNR penalty which is 1.5–2 dB less than that of LMS. Furthermore, combined with adjustable slicer threshold control, the proposed equalizer structures are demonstrated through extensive Monte Carlo simulations to achieve better performance

Adaptive Polarization Tracking and Equalization for Polarization-Diverse Intradyne Receiver of On-Off Keying (OOK)

“…In this way, the photonic energy |q(k)| 2 is free of all phase terms including frequency offset, linewidth or phase noise. To determine the decoded bits, ATC (automatic threshold control) is utilized to account for unequal noise variances of bits 1 and 0, similar to the case of direct-detection OOK [6]. As an example, Fig.…”