| 摘要 |
An optical amplifier for amplifying an optical signal, comprises an optical fiber (28; 54), doped with a rare earth element, having an input end to which the optical signal is input, and an output end; and a pumping light source (30; 68) emitting a pumping light beam to be introduced to either the input end or the output end of said optical fiber; wherein the optical signal being amplified by propagation through said optical fiber; and said pumping light source is provided for outputting a supervisory information. Moreover, an optical transmission system comprises an optical amplifier and a transmission station (21; 50) for transmitting the optical signal to the optical amplifier through an optical transmission line. Moreover, a method of amplifying an optical signal, comprising a step of emitting, from a pumping light source, a pumping light beam to be introduced to either an input end or an output end of an optical fiber doped with a rare earth element; and a step of outputting a supervisory information from the pumping light source. <IMAGE> |
