OPTICAL FIBER COUPLER AND ITS PRODUCTION AND OPTICAL COMMUNICATION SYSTEM

摘要

PURPOSE: To obtain an optical fiber coupler with which the interference of signal light hardly occurs by providing the above optical fiber coupler with a fiber type diffraction grating part which reflects light of one wavelength band and allows the transmission of light in another wavelength band. CONSTITUTION: This optical fiber coupler has an optical fiber 11 and an optical fiber 12 connected via a distribution coupling mechanism 3 to the intermediate part of this optical fiber 11. Fiber type diffraction gratings 21 and 22 respectively varying in reflection wavelength bands are imparted to the respective output sides of the optical fibers 11 and 12. The optical fibers 11, 12 are the optical fibers of quartz glass formed by doping germanium oxide in their cores. The diffraction grating 21 shuts off the wavelength band of the light signal passing the diffraction grating 22 and the diffraction grating 22 shuts off the wavelength band of the light signal passing the diffraction grating 21. The signal light does not interfere between a port 1 and a port 2 any more. An optical communication system free from crosstalks is thus constituted.