Patent ID: 8587862

Claim:
A second-harmonic generation nonlinear frequency converter, comprising: a nonlinear optical crystal, comprising: a plurality of sections, wherein the sections are connected to each other sequentially and each of the sections respectively has a period which is different from each other, and each of the periods comprises a positive domain and a negative domain, each of the sections comprising: a plurality of quasi-phase-matching structures, wherein the quasi-phase-matching structures in the same section are connected to each other sequentially and have the same period; wherein the nonlinear optical crystal satisfies the following formula: | T i −T f |=R×ΔT, 1≦ R≦ 10, wherein the Ti is the central temperature of the quasi-phase-matching structures of the section in one of the terminals of the nonlinear optical crystal, Tf is the central temperature of the quasi-phase-matching structures of the section in the other terminal of the nonlinear optical crystal, R is a proportionality constant, ΔT is the central temperature range of the quasi-phase-matching structures.