Optical amplifiers, optical communication system and networks using the amplifier and integrated optical nodes including the amplifier

摘要

In an optical amplifying apparatus of this invention, there are provided an optical amplifier part (2) for giving a gain to an input light (4) from outside and a selective loss part (1) for giving a light loss of a prescribed ratio for different polarization modes in order to compensate for a polarization dependency of the amplification on factor between the input (4) and output (5) lights. Thus, the difference of amplification factors for the different polarization modes is compensated for, as a whole of the apparatus. This polarization non-dependent type optical amplifying apparatus has solved the polarization dependency without degrading other characteristics, so that this can be preferably used in a optical communication system or network. Further, this amplifying apparatus does not require so many external optical components, so this is suitable to the fabrication of a module and is preferably contained in an integrated optical node.