| 摘要 |
PROBLEM TO BE SOLVED: To obtain characteristics satisfactory in practical use by applying a multistage constitution of MZI and a cascade connecting constitution and controlling the result of a loss characteristic of a circuit caused by forming grooves. SOLUTION: Waveguides 122-125, arm waveguides 126-131, directional couplers 132-135 and groove parts 136-138 are provided in a Si substrate 121, a silicone resin is filled in the groove parts 136-138, and input/output optical fibers 142, 143 and 144 are connected to the waveguides 123, 124 and 125 via optical fiber blocks 139, 140 and 141. A material having a temperature coefficient of a refractive index of a code different from the temperature coefficient of the effective refractive index of the optical waveguide is filled in the grooves, and an optical intensity ratio, which is branched to the long side optical waveguide of an optical waveguide pair connected to the optical coupler from the input optical waveguide in a first optical coupler, is smaller than 50%. |
