Patent ID: 6407869
Filing Date: 2002-06-18
Classification: H01S

Abstract:
An external cavity type light source comprising:a semiconductor laser coated on one end with a reflection prevention film, in which emitted light from the end face of said semiconductor laser on the reflection prevention film side is converted into collimated light and the collimated light having a wavelength selected through a diffraction grating is fed back into said semiconductor laser, and emitted light from an opposite end of said semiconductor laser is converted into collimated light and the collimated light is condensed and output to an optical fiber; a light branch element placed between the diffraction grating and said semiconductor laser; a prism placed outside an axis passing through the diffraction grating and the semiconductor laser; wherein diffracted light fed back into said semiconductor laser from the diffraction grating is made to branch through the light branch element and one branch light is taken out as output light; and wherein diffracted light from the diffraction grating is made to reflect on the light branch element, divert through the prism, and is taken out as output light.