A Simplified Feedforward Carrier Recovery Algorithm for Coherent Optical QAM System

Author

Li, Xin ; Cao, Yinwen ; Yu, Song ; Gu, Wanyi ; Ji, Yuefeng

Author_Institution

Key Lab. of Inf. Photonics & Opt. Commun. (Minist. of Educ.), Beijing Univ. of Posts & Telecommun., Beijing, China

Volume

29

Issue

5

fYear

2011

fDate

3/1/2011 12:00:00 AM

Firstpage

801

Lastpage

807

Abstract

A simplified quadrature amplitude modulation (QAM) feedforward carrier recovery algorithm is proposed. By introducing a new two-stage estimation structure and sliding-block approach, the required computational effort can be significantly reduced with a tolerable performance deterioration compared with the original algorithm. In order to choose the size of the sliding block properly, an analytical model is proposed that takes the optical SNR (OSNR) and the laser-linewidth-times symbol-rate product into account. The model reveals different influence of OSNR and the laser-linewidth-times symbol-rate product on the performance of any carrier recovery algorithm. The performance of the simplified algorithm is evaluated by Monte Carlo simulations for square 16-, 64-, and 256-QAM. The simulation results show that the computational effort for each symbol can be significantly reduced at the cost of a 11% reduction of laser linewidth tolerance.

Keywords

Monte Carlo methods; optical communication; optical modulation; quadrature amplitude modulation; Monte Carlo simulations; coherent optical QAM system; computational effort; feedforward carrier recovery algorithm; laser linewidth tolerance; laser-linewidth-times symbol-rate product; optical SNR; sliding block; two-stage estimation; Computational effort; feedforward carrier recovery (FFCR); quadrature amplitude modulation (QAM); sliding block;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2011.2106197

Filename

5688177