| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive optical branching filters/couplers which efficiently branches/couples light of plural adjacent wavelengths. SOLUTION: The optical branching filter is composed of an optical fiber 10, an optical circulator 20, optical collimators 40a-40c and an optical filter 50. Also, optical fibers 10a-10d are connected to the components, and a fiber grating 30 is formed in an optical fiber 10a. The fiber grating 30 is set so as to reflect an optical signal of wavelength λ2. The optical filter 50 is a long wavelength transmitting filter using the wavelength λ2 as the intermediate zone. When an optical multiple signal into which optical signals of three adjacent wavelengths λ1-λ3 are multiplexed is made incident from the optical fiber 10, it is demultiplexed every wavelength by the optical multiplexer/demultiplexer and demultiplexed signals propagate separate optical fibers respectively. |
