Patent ID: 6657778
Filing Date: 2003-12-02
Classification: H04B,H04J

Abstract:
An optical amplifying repeater apparatus wherein the apparatus comprises:an input port to which a plurality of light signals multiplexed in wavelength are inputted, a first fixed-gain optical amplifier for amplifying the wavelength-multiplexed light signals inputted through said input port with a predetermined gain, an adjustable optical attenuator for attenuating the wavelength-multiplexed light signals by a predetermined factor after amplification through said first fixed-gain optical amplifier, an optical demultiplexer for demultiplexing said wavelength-multiplexed light signals outputted from said adjustable optical attenuator into a plurality of individual light signals of discrete wavelengths, respectively, more than one second fixed-gain optical amplifiers for amplifying said plurality of individual wavelength-demultiplexed light signals outputted from said optical demultiplexer with a predetermined gain, a monitoring light branching device connected to one of outputs of said more than one second fixed-gain optical amplifiers for extracting a part of a specific monitoring light signal, an optical multiplexer for multiplexing the individual light signals outputted from said more than one second fixed-gain optical amplifiers, respectively, for thereby outputting multiplexed light signals, and an adjustable attenuator control circuit for detecting output power of said monitoring light branching device to thereby control the attenuation factor of said optical attenuator so that said detected output power assumes a constant value.