| 摘要 |
PROBLEM TO BE SOLVED: To enable the adjustment of a filter characteristic at an arbitrary wavelength so that the intensity of optical signal transmitted through the filter becomes a zero point wavelength by coating a partial section of at least one optical waveguide from among two optical waveguides with an organic material or a glass material having high refractive index. SOLUTION: A branching interference type wavelength filter is formed by a branching device 20, a multiplexer 21 and two asymmetric optical waveguides 3, 4 whose lengths are different from that of the composition (material) of an optical waveguide. A coating part 25 coated with an organic or glass material is formed in a part of two asymmetric optical waveguides 3, 4, whose lengths are different from that of the composition of an optical waveguide. When an organic material or a glass material having higher refractive index than air exists on the surface being in contact with a core layer in which a light beam propagates in the optical waveguides 3, 4, a photosensitive equivalent refractive index is increased. Then, the phase of light propagating through the optical waveguides 3, 4 is changed and the intensity of optical signal transmitted through the branching interference type wavelength filter is shifted in reference to the wavelength. |
