| 摘要 |
PURPOSE:To eliminate the need for a mode control part and to measure the loss of light accurately by connecting a light source, a photocoupler, and a photodetector mutually through a mode control light optical fiber and measuring back scattered light from one terminal of an optical fiber to be measured. CONSTITUTION:A pulse generator 2 generates and inputs a pulse to the laser beam source 3 with a timing signal from a signal processing part 1, emitting pulse light. This pulse light is made incident on the optical fiber 10 to be measured through a mode control optical fiber 14, a directional photocoupler 6, and a receptacle 7. The back scattered light is received by the photodetector 8 through the directional photocoupler 6 and a mode control optical fiber 15 and the signal processing part 1 calculates a loss distribution. The measured value of the light loss depends upon the mode distribution of the light greatly, so a stationary mode distribution needs to be obtained by limiting the high order mode, but the mode control optical fibers are used to eliminate the need for a mode control part. |
