| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to two-way-transmit a plurality of signal beams of wavelength bands and suppress reflection light by providing a selective reflection part including a diffraction grating selecitvely reflecting a light beam of a 1st- or a 2nd wavelength. SOLUTION: An optical signal of a 1st wavelengthλ1 made incident on a 1st port of an optical circulator 1 is emitted from a 2nd port and is made incident on a 1st direction grating 2. Since the 1st diffraction grating 2 reflects only the optical signal of the 1st wavelengthλ1, the optical signal of the 1st wavelengthλ1 is reflected by the 1st diffraction grating 2, and is emitted from a 3rd port and enters an optical fiber 7 for being transmitted. On the contrary, an optical signal of a 2nd wavelengthλ2 made incident on a 3rd pot from the optical fiber 7 is emitted from a 4th port and enters a 2nd diffraction grating 3. Since the 2nd diffraction grating 3 reflects only the optical signal of the 2nd wavelengthλ2 and transmits light of other wavelengths, the optical signal of the 2ns wavelengthλ2 is reflected by the diffraction grating 3, and emitted to from the 1st port and enters an optical fiber 6 for being transmitted. |
