| 摘要 |
PURPOSE:To enable the simultaneous passage of light for locating a fault point while using light for communication by constituting a multilayered film filter consisting of a dielectric substrate so as to have at least two pass wavelength bands. CONSTITUTION:Quartz waveguides 7, 8 are disposed with one sheet of the multilayered film filter 9 consisting of the dielectric substrate commonly across these two waveguides. The one end 9a of the filter 9 crosses the waveguide 7 at the parallel point thereof in such a case and the other end 9b of the filter 9 crosses the waveguide 8b at the prescribed point which is not the parallel point of the waveguide 8 and is curved. The crossing angle of the filter 9 and the waveguide 7 is, for example, 77 deg. (consequently, the angle of incidence of light is 13 deg.) and the crossing angle of the filter 9 and the waveguide 8b is 74 deg. (consequently, the angle of incidence of light is 16 deg.). Then, the fault points of respective light ports can be located by the light of the wavelength belonging to another pass wavelength band while the light of the wavelength belonging to one pass wavelength band is used for communication. |
