Device for suppressing transient effect of optical fiber amplifier in WDM system

A device for suppressing the transient effect of an optical fiber amplifier in a WDM system, comprising:

• an input tab for separating a portion of the input signal at a predetermined ratio;
• a photo diode for converting the optical signal incident from the input tab to an electrical signal;
• an amplifier for amplifying the electrical signal received from the photo diode;
• a low pass filter for delaying the electrical signal received from the amplifier and for outputting a delayed signal;
• a differential amplifier for outputting the pulses of an amplitude that are proportional to the voltage difference between the electrical signal received from the amplifier and the electrical signal received from the low pass filter;
• a peak voltage holder for holding the pulses received from the differential amplifier for a predetermined time and for outputting the delayed pulses;
• a first voltage comparator for comparing the amplitude of the pulses received from the differential amplifier with a predetermined positive reference voltage;
• a second voltage comparator for comparing the amplitude of the pulses received from the differential amplifier with a predetermined negative reference voltage;
• an OR gate for outputting a trigger signal if a difference between the output of the first and second voltage comparators is detected;
• a pump laser diode driver for supplying a driving voltage to a pump laser diode in response to a received pump indication signal;
• and,
• a controller for outputting the pump indication signal according to the channel variation in the system in response to the trigger signal.