| 摘要 |
PURPOSE:To obtain a light splitting circuit, which can be used for measuring both a single mode fiber and a multimode fiber, by utilizing the band width of the deflecting frequency of an acoustooptic deflector. CONSTITUTION:Light from a light sending optical fiber 1 is made to be an approximately parallel light beam by a lens 4 and inputted to an acoustooptic deflector 7. When a driving circuit 8 does not send an electric signal, the light beam is guided to an optical fiber to be measured through a lens 5 and an optical fiber 2. When the electric signal is applied from the driving circuit 8, the light beam is guided to the optical fiber to be measured through a lens 5' and an optical fiber 2', which are arranged in the direction of theta=theta1 when f=f1 in the expression in the Figure. Then the light through the lens 5 from the optical fiber to be measured is discarded to the direction of a light source at the time of OFF. At the time of ON, the light is diffracted to the direction of theta3. The light is guided to a light detector through a lens 6 and a light receiving optical fiber 3. The light through the lens 5' is discarded to the direction of a broken line at the time of OFF. At the time of ON, the light is diffracted to the direction of theta2 and guided to the light detector through the lens 6 and the light receiving optical fiber 3. |
