Title :
Amplifier-induced crosstalk in multichannel coherent lightwave systems
Author :
Agrawal, Govind P.
Author_Institution :
AT&T Bell Laboratories, Murray Hill, USA
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;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19870817
