Optical amplifiers may be useful as repeaters in coherent transmission systems with frequency-division-multiplexed channels because they can amplify all channels simultaneously. For this application the crosstalk due to the amplifier is an important parameter. Work on two-color gain saturation1,2 and interference from 1-kHz on-off switching of channels3 were reported. A ten- channel PSK system with an optical amplifier4 has been demonstrated. Here we report experimental results on AM crosstalk in a near-traveling-wave optical amplifier. The modulation frequency in the interfering channel is either 100 or 500 MHz. AM and FM crosstalk is also investigated theoretically, and the results are experimentally verified in the case of AM crosstalk. The mechanisms influencing the crosstalk are identified.
© 1988 Optical Society of AmericaPDF Article