OPTICAL BRANCHING FILTER CIRCUIT

摘要

PURPOSE:To attain a two-way transmission system between a central station using optical fibers and many terminals, by combining an optical mixing means, a filter and a lens together. CONSTITUTION:The light delivered from an element 1 that produces the light of waveform lambda1 is converted into parallel luminous fluxes through the 1st lens 2 and made incident to a filter 6 which transmits the light of waveform lambda1 and reflects the light of waveform lambda2. The light of lambda1 passes through the filter 6 to be condensed through the 2nd lens 4 and is made incident to an optical mixing means like a glass rod covered with a medium of a low refractive index. The light made incident to the mixing means is divided almost evenly into plural fibers 5. While the light of lambda2 transmitted through the fibers 5 is radiated through the mixing means and then converted into parallel luminous fluxes by the lens 4. These parallel luminous fluxes are all reflected at the filter 6 and then condensed through a lens 8 to be made incident to a photodetector 7.