Patent ID: 6900931
Filing Date: 2005-05-31
Classification: H01S,H04B

Abstract:
1. An optical amplification device, comprising: a first segment of active optical fiber having a first end portion coupled to an optical communication path carrying a plurality of optical signals, each at a respective one of a plurality of wavelengths, and a second end portion, said first segment of active optical fiber receiving the plurality of optical signals through the first end portion and outputting the plurality of optical signals through the second end portion; a dispersion compensating element optically coupled to the second end portion of said first segment of active optical fiber; a second segment of active optical fiber having a first end portion coupled to said dispersion compensating element and carrying a plurality of dispersion compensated optical signals, each at a respective one of a plurality of wavelengths, and a second end portion, said second segment of active optical fiber receiving the plurality of optical signals through the first end portion and outputting the plurality of dispersion compensated optical signals through the second end portion; a variable optical attenuator having an input port coupled to the second end portion of said second segment of optical fiber, said variable optical attenuator having a control port that receives an attenuation control signal and an output port, said input port of said variable optical attenuator receiving the plurality of dispersion compensated optical signals; a third segment of active optical fiber having a first end portion coupled to the output port of said variable optical attenuator and a second end portion, the plurality of dispersion compensated optical signals propagating through said variable optical attenuator and being supplied to the first end portion of said third segment of active optical fiber via the output port of said variable optical attenuator, the plurality of dispersion compensated optical signals being output from said third segment of active optical fiber via the second end portion of said third segment of active optical fiber; and a control circuit operatively coupled to the optical communication path, said control circuit sensing an input optical power of at least one of the plurality of optical signals input to the first end of said first segment of active optical fiber said variable optical attenuator attenuating the plurality of optical signals in response to the attenuation control signal such that a gain profile of the plurality of dispersion compensated optical signals output from the second end portion of said third segment of active optical fiber is flattened, said control circuit including an attenuator offset value storage device operatively connected to said control circuit, said attenuator offset value storage device storing an attenuator offset value, wherein said attenuator offset value substantially minimizes non-flatness of an output spectrum output from the optical amplification device; said control circuit inputting the attenuator offset value from said attenuator offset value storage device and outputting the attenuation control signal in response to the input optical power and the attenuator offset value.