| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength converting element which can convert a plurality of input light wavelengths arranged at irregular intervals and has small decrease in conversion efficiency. SOLUTION: A nonlinear medium of the wavelength converting element has a modulation structure which has a nonlinear optical constant of a periodΛ<SB>0</SB>in a traveling direction of light, the phase continuously changing every periodΛ<SB>0</SB>and continuous phase modulation in a different periodΛ<SB>ph</SB>being added. Further, the nonlinear medium has a modulation structure such that a modulation curve of phase modulation is varied so that at least three peaks of conversion efficiency arranged at irregular intervals among peaks of conversion efficiency where a phase mismatching amountΔβrepresented asΔβ=2π(n<SB>3</SB>/λ<SB>3</SB>-n<SB>2</SB>/λ<SB>2</SB>-n<SB>1</SB>/λ<SB>1</SB>) is given by 2π/Λ<SB>0</SB>+2πi/Λ<SB>f</SB>(i=m, m+1, ..., n:m, n is positive or negative integers) become maximum, where n<SB>1</SB>, n<SB>2</SB>, and n<SB>3</SB>are refractive indexes to wavelengthsλ<SB>1</SB>,λ<SB>2</SB>, andλ<SB>3</SB>. COPYRIGHT: (C)2008,JPO&INPIT
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