Patent ID: 7034990

Claim:
A wavelength conversion element having a periodic structure for demonstrating quasi-phase matching, with a period Λ thereof being set to a value satisfying the following formulas (1), (2), (3), and (4): (2π/λ SF ) n SF −(2π/λ 1 ) n 1 −(2π/λ 2 ) n 2 =2π/Λ (1) (2π/λ SF ) n SF −(2π/λ S ) n S −(2π/λ C ) n C =2π/Λ (2) 1/λ SF =1/λ 1 +1/λ 2 (3) 1/λ SF =1/λ S +1/λ C (4), in which: λ 1 is a wavelength of a first pump light inputted in the wavelength conversion element; λ 2 is a wavelength of a second pump light inputted in the wavelength conversion element; λ S is a wavelength of a signal light inputted in the wavelength conversion element; λ C is a wavelength of a converted light inputted in the wavelength conversion element; λ SF is a wavelength of a sum frequency light of the first pump light and second pump light; n SF is a refractive index of the wavelength conversion element with respect to the sum frequency light of the first pump light and second pump light; n 1 is a refractive index of the wavelength conversion element with respect to the first pump light; n 2 is a refractive index of the wavelength conversion element with respect to the second pump light; n S is a refractive index of the wavelength conversion element with respect to the signal light; and n C is a refractive index of the wavelength conversion element with respect to the converted light.