Coherent light source and an optical device

Conventionally, the number of parts, since the optical system is complex, miniaturization of the optical system, stabilization, it is difficult to higher output, further, with respect to the optical axis of the fundamental wave incident light generation optical axis harmonic for an angle, there is a problem that it is difficult optical axis adjustment. Therefore, the coherent light source of the present invention, narrow band pass characteristic with respect to a portion of the light source and the wavelength conversion element for converting the harmonic part of the emitted fundamental wave from the light source, not converted into a harmonic fundamental wave and a wavelength selective filter having a transmission characteristic with respect to a, and harmonics. Some of the fundamental wave that is not converted into a harmonic wave emitted from the wavelength conversion element is fed back to the light source by the wavelength selection filter, harmonic, characterized in that it is emitted to the outside through the wavelength selective filter. Thus, a high output and stable, short wavelength light source with excellent mass productivity can be realized.