Patent ID: 7969648
Filing Date: 2011-06-28
Classification: H01S,H04B

Abstract:
1. An apparatus comprising: a plurality of optical amplifiers optically connected together so that a wavelength division multiplexed (WDM) signal light is amplified by each of the optical amplifiers, each optical amplifier having a gain related to a ratio of a power level of the WDM signal light input to the respective optical amplifier to a power level of the WDM signal light output from the respective optical amplifier; a variable attenuator optically connected between respective optical amplifiers of the plurality of optical amplifiers; a controller detecting power levels of the WDM signal light input to, and output from, each optical amplifier of the plurality of optical amplifiers and, in accordance with all the detected power levels, controlling attenuation of the variable attenuator to thereby cause the sum of the gains of all the optical amplifiers of the plurality of optical amplifiers to be constant.