| 摘要 |
PURPOSE:To obtain good branching characteristics by interposing a prism and multilayer film filters between two refractive index distribution type rod lenses. CONSTITUTION:Multilayer film filters 3, 12 which transmit the light of a wavelength lambda1 and reflect the light of a wavelength lambda2 and a rectangular prism 11 of 45 deg. in vertex angle are inserted between refractive index distribution type rod lenses 1, 2 of a 1/4 period length. Then, the light of the wavelengths lambda1, lambda2 having been transferred in an optical fiber 4 is converted to parallel fluxes by the rod lens 1, after which the parallel fluxes by the rod lens 1, after which the parallel fluxes enter the multilayer film filter 3, by which the light of the wavelength lambda2 is reflected. This light is then stopped down by the rod lens 1 and is entered to an optical fiber 5. The light of the wavelength lambda1 having transmitted through the multilayer film filter 3 and the remained light of the wavelength lambda2 are totally reflected by the tapered face of the rectangular prism 11. In the multilayer film 12 the remained light of the wavelength lambda2 is removed and only the light of the wavelength lambda1 is stopped down by the rod lens 13 and enters the optical fiber 6. Hence, the unnecessary transmitted light and reflected light are removed by the multilayer film filters 3, 12 and the intended object may be achieved. |
