Frequency-Domain Chromatic Dispersion Equalization Using Overlap-Add Methods in Coherent Optical System

TL;DR

This paper introduces overlap-add zero-padding methods for frequency-domain chromatic dispersion equalization in high-speed coherent optical systems, demonstrating comparable performance to traditional methods with optimized computational efficiency.

Contribution

It presents novel overlap-add zero-padding techniques for FDEs in optical systems, including derivation of minimum overlap and analysis of FFT length for reduced complexity.

Findings

OLA-ZP methods achieve similar performance to overlap-save

Optimal FFT length minimizes computational complexity

Minimum overlap required for effective dispersion compensation

Abstract

The frequency domain equalizers (FDEs) employing two types of overlap-add zero-padding (OLA-ZP) methods are applied to compensate the chromatic dispersion in a 112-Gbit/s non-return-to-zero polarization division multiplexed quadrature phase shift keying (NRZ-PDM-QPSK) coherent optical transmission system. Simulation results demonstrate that the OLA-ZP methods can achieve the same acceptable performance as the overlap-save method. The required minimum overlap (or zero-padding) in the FDE is derived, and the optimum fast Fourier transform length to minimize the computational complexity is also analyzed.