Patent ID: 6366393
Filing Date: 2002-04-02
Classification: H01S,H04B

Abstract:
An arrangement for controlling the gain of an optical amplifier coupled to an optical fiber in a wavelength division multiplexed (WDM) system, the optical amplifier coupled to a pump source and capable of amplifying a WDM signal having a plurality of optical channels, the arrangement comprising:a feed-forward monitoring path, coupled to the optical fiber at a position upstream from an input of the optical amplifier, for measuring input power to the optical amplifier; and a control circuit, responsive to the measured input power, for controlling an amount of pump power supplied by the pump source to the optical amplifier, the amount of pump power for effecting gain control being a function of a scaled relationship to the measured input power, the scaled relationship being derived using a first coefficient representative of a direct offset value to the pump power and a second coefficient representative of a slope factor corresponding to a predetermined relationship between the pump power and the measured input power, whereby per-channel gain in the amplified WDM signal is maintained so that power excursions in one or more of the optical channels being amplified are substantially limited in the presence of changes in input power to the optical amplifier.