Patent ID: 7535632
Filing Date: 2009-05-19
Classification: H01S,H04B

Abstract:
1. A method for compensating a variation in gain in an optical amplifier for amplifying an optical Wavelength Division Multiplexing signal, comprising: providing a plurality of series-connected amplifier stages with at least two pumping devices; adjusting a pumping power of the pumping devices to keep a amplifier gain essentially constant when an abrupt change of an input power occurs; adjusting the pumping power of a first amplifier stage when the abrupt change in the input power occurs; determining an expected change in the input power at a succeeding second amplifier stage; determining a new pumping power for the pumping device associated to a second amplifier stage based upon the determined expected change in the input power at the second amplifier stage; and adjusting the new pumping power for the second amplifier stage based upon a derivative time before the abrupt change in power occurs at the input of the second stage.