| 摘要 |
PURPOSE:To prevent mixture of different wavelength components, by taking out the light in each wavelength component through filter after distributing the light propagated through one optical fiber or optical fiber bundle in the light distributing section. CONSTITUTION:A light 6 of wavelengths lambda1 and lambda2 propagated through an optical fiber 3 is distributed into an optical fiber 4 and an optical fiber 5 in a light distributing section 11. The wavelength lambda1 component of the light 12 sent into the optical fiber 14, while the wavelength lambda2 component of the light 13 sent into the optical fiber 5 is picked up by a photo detector 10 through a low pass filter 15. Though the wave 4 is picked up by a photo detector 9 through a high pass filter length characteristics of both filters 14, 15 have slight reflection properties at the transmission wavelength, the light of wavelength lambda1 component slightly reflected by the high pass filter 14 is not sent into the optical fiber 5 in the light distributing section 11, and the light of wavelength lambda2 component slightly reflected by the low pass filter 15 is not sent into the optical fiber 4. Therefore, only the light of wavelength lambda1 component enters the photo detector 9, while only the light of wavelength lambda2 component enters the photo detector 10. |
