| 摘要 |
PURPOSE:To keep a by-pass level accurately even if optical fiber length is changed by combining a pair of optical fibers having collimating lenses with a pair of ones having lenses provided with a beam splitter and a reflector. CONSTITUTION:Light projected from an optical fiber 1 is transmitted to a beam splitter film 4b fitted to a deffraction index distribution type lens 4 at a fixed rate and a half of the transmitted light is reflected by a reflector 8a of a cubic prism 8, passed through a lens 5 and coupled with an optical fiber 2, and the remaining half light is transmitted into the prism 8, made fall upon a lens 7, reflected by a reflecting film 7a, also reflected by the reflecting film 8a of the prism 8, and then coupled and transmitted to an optical film 3 through a lens 6. A half of the light projected from the optical fiber 2 is coupled and transmitted to the optical fiber 3 and the remaining half light is coupled with the optical fiber 1 and a part of the remaining half light is also coupled and transmitted to the optical fiber 3. |
