LIGHT AMPLIFIER

摘要

PURPOSE:To enable a light amplifier to be kept constant in gain without detecting its input and output light signals. CONSTITUTION:A rare earth-added optical fiber light amplifier of light bumping type is equipped with means 9 and 12 which detect the pumping light power that impinges on the rare earth-added optical fiber and an output pumping light power which passes through the rare earth-added optical fiber respectively and a means 11 which controls the light source of pumping light so as to make the ratio of am impinging pumping light power to an output pumping light power constant.