| 摘要 |
PROBLEM TO BE SOLVED: To improve wavelength conversion efficiency of a wavelength conversion element in which a ferroelectric crystal substrate having a periodical polarization inversion structure formed by a voltage application method is adhered to a support substrate.SOLUTION: A wavelength conversion element 14 includes: a support substrate 9; a ferroelectric crystal substrate 1A composed of a Z-cut substrate or an off-cut Z-cut substrate of a ferroelectric crystal and having a first major surface and a second major surface; a periodical polarization inversion structure 7A provided in the substrate 1A; an optical waveguide provided in the substrate 1A; and an adhesive layer 12 adhering the second major surface 1b of the substrate to the support substrate 9. The periodical polarization inversion structure 7A is formed by applying a voltage between a plurality of electrode pieces provided on a first major surface 1a of a substrate 1 and a uniform electrode on an insulating film provided on a second major surface 1b of the substrate, and is formed into a thin film by polishing the first major surface 1a of the substrate. |
