Observation of crosstalk due to four-wave mixing in a laser amplifier for FDM transmission

Abstract

Crosstalk due to four-wave mixing in a semiconductor laser amplifier for optical FDM (frequency-division multiplexing) transmission is reported. Even when a laser amplifier is used in constant-power modulated FDM transmission, four-wave mixing in the amplifier causes channel crosstalk. In an experiment on three-channel amplification, where signals are frequency-modulated, a crosstalk of – 30 dB is measured. This crosstalk is strongly dependent on channel separation and optical power