| 摘要 |
PURPOSE:To obtain a light splitting circuit, which can be used both for a single mode optical fiber to be measured and a multimode optical fiber to be measured, by utilizing the symmetric property of incident light angles with respect to the acoustic wave front from 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 at a specified incident angle. When an electric signal is not applied from a driving circuit 8, the light beam is guided to an optical fiber to be measured through a lens 5 and an optical fiber 2. When the signal is applied from the circuit 8 to the deflector 7, 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 theta obtained by the expression in the Figure. The light from the optical fiber to be measured through the optical fiber 2 and the lens 5 is discarded in the direction of a light source at the time of OFF. At the time of ON, the light is diffracted and guided to a light detector through a lens 6 and a light receiving optical fiber 3. The light passing the lens 5' is discarded to the direction of the light source at the time of ON and guided to the light detector at the time of OFF. |
