OPTICAL FIBER AMPLIFIER

摘要

An optical fiber amplifier including a first optical fiber doped with erbium andphosphorous, for amplifying signal light excited by the erbium, a second opticalfiber connected to one end of the first optical fiber, doped with erbium and aluminum, and having a gain spectrum slope opposite to the first optical fib er according to population inversion of the erbium, for amplifying signal light output by the first optical fiber, a pumping laser source connected to the other en d of the first optical fiber, for exciting the erbium of the first and second optical fibers, and a light coupler for coupling pumping light from the pumping laser source to the signal light and outputting the resultant light to the first optical fiber. Two types of EDFs having different gain spectrums are used, such that the gain spectrum o f each of the EDFs actively varies with the input signal light power or pumpin g light power. Thus, an entirely flat gain is kept.