Patent ID: 7236674

Claim:
An optical waveguide device comprising: a substrate composed of a nonlinear optical material and a periodically domain-inverted structure having the same composition as the nonlinear optical material, wherein the domain-inverted structure has a refractive index distribution relying on the domain-inverted structure, the nonlinear optical material is a Mg-doped LiNbO 3 crystal, a phase matching wavelength harmonizes with a Bragg reflection wavelength, and the Bragg reflection wavelength λ satisfies a relationship of λ 1 <λ<λ 2 when λ 1 =635+48×n (nm), λ 2 =1.02×λ 1 (nm) where (n=0, 1, 2), or λ 1 =774+40×n (nm), λ 2 =1.02×λ 1 (nm) where (n=0, 2, 3, 4 . . . ).