OPTICAL AMPLIFIER AND METHOD AS WELL AS OPTICAL TRANSMISSION SYSTEM HAVING OPTICAL AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To provide an optical amplifier device capable of independently controlling the signal light outputs of individual wavelengths with a wavelength multiplex transmission system, increasing system series at a low cost and independently controlling the signal light progressing in directions reverse from each other in a bidirectional optical transmission system. SOLUTION: The signal light introduced from one or plural transmission signal light input ports 2 is introduced from a polarized wave identifying and synthesizing means 3 to a polarized wave holding and optical amplifying medium 4. This optical amplifying medium 4 is selectively excited by an exciting means 6 and the amplified light signal is identified and separated by a polarized wave separating means 7, following which the separated light signals are partly branched by a branching means 18. The branched light detected by a detecting means 9 is so controlled by the exciting means 6 as to be controlled to a predetermined value and the greater part of the light is led out of one or plural output ports 11 to parallel transmission fibers.