Amplifier-induced crosstalk in multichannel coherent lightwave systems

Author

Agrawal, Govind P.

Author_Institution

AT&T Bell Laboratories, Murray Hill, USA

Volume

23

Issue

22

fYear

1987

Firstpage

1175

Lastpage

1177

Abstract

When an in line semiconductor laser amplifier is used to amplify several channels simultaneously, it can induce inter channel crosstalk if the amplifier gain is channel-dependent. It is shown that modulation of the carrier density at the beat frequency of two neighbouring channels can lead to considerable crosstalk even when the amplifier is operated well below the saturation level. An analytic expression for the channel gains of a travelling-wave amplifier is used to discuss and compare the crosstalk for ASK and FSK systems. The relatively short carrier lifetime in high-gain amplifiers may ultimately limit the channel spacing of such multichannel systems.

Keywords

amplitude modulation; crosstalk; frequency shift keying; optical communication equipment; semiconductor junction lasers; ASK systems; FSK systems; analytic expression; beat frequency of two neighbouring channels; carrier density modulation; channel spacing; high-gain amplifiers; in-line semiconductor laser amplifier; inter-channel crosstalk; laser amplifier induced crosstalk; multichannel coherent lightwave systems; multichannel systems; short carrier lifetime; travelling-wave amplifier;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19870817

Filename

4259056