Laser linewidth requirements for optical DQPSK systems

Author

Savory, Seb ; Hadjifotiou, Anagnostis

Author_Institution

Nortel Networks, Harlow, UK

Volume

16

Issue

3

fYear

2004

fDate

3/1/2004 12:00:00 AM

Firstpage

930

Lastpage

932

Abstract

A differential quadrature phase-shift-keying (DQPSK) system is analyzed in the presence of additive optical noise and phase noise. In DQPSK, the impact of laser linewidth is frequently neglected: This letter aims to determine whether this assumption is valid. Using asymptotic techniques, we determine the effect that phase noise has on the bit-error rate (BER); this leads to a simple condition for when laser linewidth may be neglected. For a 10-GBd DQPSK system operating at a BER of 10^-3, a linewidth of less than 3 MHz is required for the signal-to-noise-ratio penalty to be less than 0.1 dB.

Keywords

differential phase shift keying; distributed feedback lasers; error statistics; optical fibre communication; optical noise; phase noise; quadrature phase shift keying; semiconductor lasers; 10 Gbit/s; BER; DQPSK systems; additive optical noise; bit-error rate; differential quadrature phase-shift-keying; laser linewidth; phase noise; signal-to-noise-ratio penalty; Bit error rate; Fiber lasers; Laser noise; Optical filters; Optical interferometry; Optical noise; Optical receivers; Phase noise; Phase shift keying; Signal to noise ratio;

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2004.823720

Filename

1269843