| 摘要 |
PROBLEM TO BE SOLVED: To obtain a Gauss beam state wavelength converting wave and to obtain high wavelength conversion efficiency by providing a light shielding plate for cutting the side lobe of the wavelength converting wave emitted from a wavelength type light wavelength converting element after setting the waveguide type light wavelength converting element, so that the phase of the wavelength converting wave propagated in an optical waveguide in a primary mode matches with that of fundamental wave. SOLUTION: This device is provided with an enlarging lens 13 for enlarging the beam spot of second higher harmonic 12, emitted from the waveguide type light wavelength converting element 11. It is provided with a knife edge 15 which functions as the light shielding plate arranged at the converging position of the wave 12 by the lens 13. The higher harmonics 12 emitted after it is propagated through the channel optical waveguide in the primary mode has a side lobe, and the knife edge 15 is arranged to extend over the part of the side lobe. Therefore, the side lobe is vignetted by the knife edge 15 and the higher harmonic 12 after passing through the knife edge 15 becomes substantially Gaussian beam.
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