| 摘要 |
PURPOSE:To efficiently fold an exciting light by increasing a reflection attenuating amount of a signal light. CONSTITUTION:An exciting light/signal light separating filter 13 having characteristics for transmitting an exciting light 15 and reflecting a signal light 3 to an output end of a rare earth element-doped optical fiber 5, is obliquely disposed, and a mirror 14 for reflecting a transmitted exciting light is disposed perpendicularly to the exciting light. The light 15 is transmitted through the filter 13, reflected by the mirror 14, again transmitted through the filter 13, and folded to the fiber 5. The light 3 is reflected to be output by the filter 13. The light 3 is attenuated by 60dB or more by the filter 13. |
