Block decision-aided laser phase noise estimation for coherent optical OFDM systems

In this paper, we propose a block decision-aided (BL-DA) laser phase noise (LPN) estimation algorithm for coherent optical OFDM (CO-OFDM) systems. The OFDM symbols are divided into several blocks and the LPN estimation and compensation procedure is performed based on the decisions between these blocks. The proposed BL-DA algorithm can be applied for higher LPN estimation while at the same time ensuring a better estimation performance. Simulations are carried out in a 70.6 Gbit/s 16-QAM CO-OFDM system to verify the feasibility and efficiency of the BL-DA algorithm.

1. Introduction

Coherent optical orthogonal frequency division multiplexing (CO-OFDM) has been an attractive technology for long-haul optical communication systems due to its high spectral efficiency and excellent tolerance to fiber chromatic dispersion (CD) and polarization mode dispersion (PMD) [1]. However, due to its longer symbol duration compared with a single carrier system, CO-OFDM is more sensitive to the laser phase noise (LPN).