| 摘要 |
PURPOSE:To reduce the crosstalk due to the optical signal which should be reflected on a filter chip at a branch point, by interposing a wavelength selective filter in a point other than the branch point on the way of the optical path of an optical fiber for main path. CONSTITUTION:An optical fiber 11 for main path and an optical fiber 12 for branch path are fixed to a substrate, and a slit 14 where a wavelength selective filter chip 15 is inserted is arranged at a branch point A' of the fiber 11. A wavelength selective filter 16 is arranged at a prescribed angle on the side opposite to the fiber 12 side of the chip 15 on the optical path of the fiber 11. The optical signal having a wavelength lambda1 which is made incident on one end part of the fiber 11 is propagated through the filter 16 and the chip 15, and the optical signal having a wavelength lambda2 which is made incident on the other end part is reflected on the chip 15 and is propagated to the fiber 12 but a part of this signal is transmitted through the chip 15. Since the optical signal transmitted through the chip 15 is reflected on the filter 16 by this constitution, the occurrence of crosstalk is prevented. |
