| 摘要 |
An array waveguide diffraction grating 201 as waveguide type optical device comprises a planar lightwave circuit 203 with an optical waveguide layer 211 formed on a silicon substrate 212 and having a predetermined thickness h<SUB>0</SUB>, a first compensation substrate 204 bonded to the side of the optical waveguide layer 211 and having a thickness h<SUB>1 </SUB>and a second compensation substrate 205 formed on the silicon substrate 212 and having a thickness h<SUB>4</SUB>. The linear expansion coefficients alpha<SUB>1 </SUB>and alpha<SUB>4 </SUB>of the two compensation substrates 204 and 205 are set to be greater than that of the optical waveguide element 203, and highly rigid adhesives are used as a first and a second adhesive 214 and 215. It is thus possible to have the contraction of the optical waveguide element 203 due to a temperature change increased with the first and second substrates, thus permitting the center frequency setting to a desired value in a predetermined temperature range. Similar effects are obtainable by merely providing a support substrate on the substrate side of the optical waveguide element 203.
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