| 摘要 |
PURPOSE:To obtain a light splitting circuit, in which both a single mode fiber and a multimode fiber are used as a fiber to be measured, by improving the band width of the deflecting frequency of an acoustooptic deflector and the conditions of incident angles. 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 signal from a driving circuit 8 is applied through a first channel 7', the beam is diffracted to the direction theta, which is imparted by the expression in the Figure. Namely, when f=f1, theta=theta1 is obtained. When f=f2, theta=theta2 is obtained. The light beams are guided to an optical fiber to be measured through a lense 5 or 5' and an optical fibers 2 or 2'. When a signal from a driving circuit 8' is applied to the light from the optical fiber to be measured through a second channel 7'', the light is diffracted and guided to a light detector through a lens 16 and a light receiving optical fiber 3. In correspondence with the kind of the optical fiber to be measured, the fiber is connected to either of the optical fiber 2 or 2'. The other fiber is closed. Thus the optical pulse tester can be used for both a single mode fiber and the multimode fiber. |
