Abstract: The working conditions of NOLM regenerator are analyzed according to its regenerating theory. By defining the power fluctuation parameter of NOLM regenerator, it is required that the power deviation of received signal amplified by EDFA towards the optimal point should be less than 10%, and the total walkoff between signal and probe pulses should be smaller than half of the signal pulse interval.In order to restrain the crosstalk induced by NOLM, the walkoff between pulses needs to be adjusted according to the received signal. Provided that the clock pulse is located at the center of the switch window, the generated signal will beobtained without spectral shift.

Key words: optical fiber communication systems, regenerator, cross-phase modulation, NOLM