PLANAR WAVEGUIDE TYPE VARIABLE OPTICAL ATTENUATOR

摘要

PROBLEM TO BE SOLVED: To provide a planar waveguide type variable optical attenuator which has an optical characteristic in which a polarization dependency loss is small even in the case of large optical attenuation quantity and also has high mechanical strength, and for which the manufacturing time is short. SOLUTION: This planar waveguide type variable optical attenuator 1 comprises a base board 100 and a Mach-Zehnder interferometer 101 composed of two optical waveguide arms 10 and 20 embedded in a clad 70 formed on the base board and having an optical path differenceΔL0 and thin film heaters 110 and 120 arranged on the surface of the clad 70 and for adjusting the optical lengths of the optical waveguide arms 10 and 20. The optical waveguide arms 10 and 20 are made from silica glass material, and the optical path differenceΔL0 is set between 0.38 and 0.53μm.