| 摘要 |
PURPOSE:To vary the quantity of attenuation of light with a simple constitution to miniaturize an optical attenuator by providing a fixed rod lens and a mobile rod lens in a cylinder holder of the optical attenuator and moving the mobile rod lens in the cylinder holder. CONSTITUTION:An optical attenuator 1 is arranged between a photodetector 2 and an optical fiber 4 fixed to an optical fiber holder 3, and this attenuator 1 consists of a cylinder holder 5 and converting rod lenses 6 and 7 fitted in this holder 5. The rod lens 6 is fixed to the side end part of the fiber 4, and the rod lens 7 is fitted to the end part of the holder 5 on the side of the photodetector 2 so that it can be freely slided in the direction of the optical aixs. Parallel rays of light are always made incident on the rod lens to fix the inter-image distance and the rod lens 7 is moved in the direction of the optical axis to move an image forming point 11 in the same direction by the same extent. |
