Patent ID: 7268936

Claim:
An optical amplifier having a polarization mode dispersion compensation function comprising: a polarization control section that is configured to control a polarization plane angle of input signal light to produce variable polarization states; a polarization mode dispersion generation section that has an optical transmission medium which has birefringence set to give a differential group delay between orthogonal polarization mode components of the signal light controlled in said polarization control section, and which is doped with a rare earth element; a pumping light supply section that is configured to apply pumping light capable of pumping said rare earth element, to the optical transmission medium in said polarization mode dispersion generation section; a monitoring section that is configured to monitor a polarization mode dispersion generation state of the signal light output from said polarization mode dispersion generation section; and a control section that is configured to control said polarization control section so that polarization mode dispersion monitored in said monitoring section, is reduced.