Patent ID: 6157481
Filing Date: 2000-12-05
Classification: H01S,H04B,H04J

Abstract:
An apparatus comprising:an optical amplifier which amplifies an optical signal having a variable number of channels associated with different wavelengths, and maintains flatness of gain with respect to the different wavelengths; anda controller having a constant gain mode in which the optical amplifier is controlled to amplify the optical signal with an approximately constant gain, the controller being operable in the constant gain mode when the number of channels is being varied, wherein the optical amplifier comprisesa first-stage optical amplifier which amplifies the optical signal to produce a firststage amplified optical signal,a level controller which controls a power level of the first-stage amplified optical signal to produce a level controlled optical signal, anda second-stage optical amplifier which amplifies the level controlled optical signal to produce a second-stage amplified optical signal.