CROSSTALK IN 1.5-MU-M INGAASP OPTICAL AMPLIFIERS

A dynamical model for multichannel amplification by near-traveling-wave optical amplifiers is presented, and results on crosstalk induced by either amplitude modulation or frequency modulation are given. The mechanisms influencing the crosstalk most are the residual facet reflectivities and the detuning of the channels relative to the amplifier Fabry-Perot spectrum. Calculations of worst-case crosstalk levels are included. The model is verified experimentally for amplitude-modulated signals, and crosstalk levels up to -7dB are reported. For frequency-modulated signals, estimated crosstalk is significantly lower and can be reduced by high quality facet coatings.