To stabilize an output and an oscillation wavelength of a semiconductor laser element in a light source device equipped with the semiconductor laser element and a second harmonic generation element.
In the light source device equipped with the semiconductor laser element 31 and the second harmonic generation element 41 with a periodical polarization reversal structure formed on an optical waveguide thereof, wherein the second harmonic generation element 41 has the optical waveguide of which the one side is assumed to be exposed, formed thereon, light emitted from the semiconductor laser element 31 is made incident on the optical waveguide of the second harmonic generation element 41 and the second harmonic of the incident light is emitted, a component with a refractive index lower than that of the optical waveguide is applied and formed on the surface of the second harmonic generation element 41 where the optical waveguide is exposed.
ISHII TOMOYUKI
MANO KOZO
