摘要 |
PROBLEM TO BE SOLVED: To suppress a power variation resulting from a return of return light when generating a harmonic in high performance.SOLUTION: A wavelength conversion element includes a cycle polarization inversion structure which converts a wavelength of a fundamental wave to generate wavelength conversion light. In the cycle polarization inversion structure, polarization inversion parts and noninversion parts are alternately formed. The cycle polarization inversion structure includes a duty factor variation portion suppressing return light. |