| 摘要 |
<p>The external resonator type laser light source of the present invention is equipped with a rotation mechanism for varying a selected wavelength according to the angle of a mirror (3), and a semiconductor laser (1) provided with a reflection preventive film (1A) on one end surface, and which converts outgoing light from an end surface on the reflection preventive film side of the semiconductor laser to parallel light, returns this parallel light to a diffraction grating (2) with the mirror after selecting the wavelength of this parallel light with the diffraction grating, and excites the laser by again selecting a wavelength with the diffraction grating and returning the light to the semiconductor laser; wherein, a photodiode (14) is provided that couples either outgoing light (A) from the end surface of the semiconductor laser not provided with the reflection preventive film or zero-order light (B) of the diffraction grating to an optical fiber (9), and receives into which any of the light is not used for coupling to the optical fiber. <IMAGE></p> |
