摘要 |
The present invention relates to an optical attenuator or the like which is easy to manufacture and is able to be miniaturized. In an optical attenuator according to this invention, a plurality of Mach-Zehnder-type waveguide elements are arranged in parallel on the common substrate. Each Mach-Zehnder-type waveguide element is provided with an input optical waveguide, a first directional coupler, two optical waveguides, a second directional coupler, an output optical waveguide, a monitoring optical waveguide and a temperature regulator for regulating the temperature of one of the two optical waveguides. Particularly, between the Mach-Zehnder-type waveguide elements adjacent to each other, an monitoring optical waveguide of one thereof and an output optical waveguide of the other thereof are arranged to cross.
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