| 摘要 |
PROBLEM TO BE SOLVED: To provide a Mach-Zehnder (MZ) optical modulator in which each electrode is electrically separated on an optical waveguide, and a change in refractive index of a separation groove part is reduced.SOLUTION: An optical modulation waveguide of the invention comprises: an optical waveguide that includes a substrate, a lower n-type nitride-based semiconductor cladding layer formed on the substrate, a nitride-based semiconductor core layer, an i-type nitride-based semiconductor cladding layer formed on at least one of upper and bottom surfaces of the nitride-based semiconductor core layer, and an upper n-type nitride-based semiconductor cladding layer formed so as to sandwich the i-type nitride-based semiconductor cladding layer and the nitride-based semiconductor core layer with the lower n-type nitride-based semiconductor cladding layer, and that is laminated in a C-axis direction; a plurality of electrodes provided on the optical waveguide; and separation grooves provided between the plurality of electrodes by removing the upper n-type nitride-based semiconductor cladding layer. The separation grooves are filled with a filler material having a lower refractive index than that of the nitride-based semiconductor core layer with respect to a predetermined wavelength. |
