Patent ID: 6577439
Filing Date: 2003-06-10
Classification: H01S,H04B,H04J

Abstract:
An optical amplifier comprising:a first wavelength multiplexing unit for multiplexing a signal light and a pumping light source so as to output the signal light and the pumping light; a first optical amplifying medium for amplifying the signal light by utilizing the pumping light and providing an output of amplified signal light; a first demultiplexing unit for receiving the amplified signal light and the pumping light and for separately outputting the amplified signal light and the pumping light; a first dispersion compensation unit for receiving the amplified signal light from the first demultiplexing unit and modifying a waveform of the amplified signal light so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and providing an output of a waveform modified signal light; a second wavelength multiplexing unit for multiplexing the waveform modified signal light received from the first dispersion compensation unit and the pumping light received from the first demultiplexing unit without passing through the first dispersion compensation unit so as to output the waveform modified signal light and the pumping light; a second optical amplifying medium for amplifying the waveform modified signal light by utilizing the pumping light an output of amplified waveform modified signal light wherein a reduction of optical signal level due to loss by the first dispersion compensation unit is suppressed; a second demultiplexing unit for receiving the amplified signal light and the pumping light received from the second optical amplifying medium and for separately outputting the amplified signal light and the pumping light; a second dispersion compensation unit for receiving the amplified signal light from the second demultiplexing unit and modifying a waveform of the amplified signal light so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and providing an output of a waveform modified signal light; a third wavelength multiplexing unit for multiplexing the waveform modified signal light received from the second dispersion compensation unit and the pumping light received from the second demultiplexing unit without passing through the second dispersion compensation unit so as to output the waveform modified signal light and the pumping light; and a third optical amplifying medium for amplifying the waveform modified signal light by utilizing the pumping light and providing an output of amplified waveform modified signal light as the signal light output of the optical amplifier wherein a reduction of optical signal level due to loss by the second dispersion compensation unit is suppressed.