Apparatus for controlling gain of an optical fiber amplifier and method thereof

摘要

A method and apparatus for controlling gain of an optical fiber amplifier includes a plurality of optical isolators, an excitation light source, a wavelength division optical fiber coupler, and a special optical fiber. At least one of the optical isolators is disposed at both input and output ports of the optical fiber amplifier so that an input signal light can propagate in one direction. The wavelength division optical fiber coupler couples excitation light from the excitation light source to the input signal light or separates one of the excitation light and the input signal light from the other.