| 摘要 |
PURPOSE:To enable removing a condenser to make parallel rays and to obtain a simple and inexpensive compensating device by using a reflection type hologram as a reflection type grating. CONSTITUTION:At a definite interval from the both ends of a laser diode 7, a reflection type hologram 8 in one direction and a condenser 9 in the other direction are installed on the same optical axis of the laser diode 7. The condenser 9 is not a lens for irradiating parallel rays against a reflection type grating. If monitor light 11 is projected on the reflection surface 13 of the reflection type hologram 8, the reflected and diffracted light 12 of fixed wave length lambda0 accurately returns to the gate of monitoring laser. If the wave length lambda0 is varied due to change of environmental temperature, the reflected light 16 is condensed at a different position from the gate of monitoring of the laser diode 7. Consequently, the wave length of the reflected light 12 entered into the laser diode 7 is only the accurate wave length lambda0 and laser light of accurate single wave length lambda0 comes out through the condenser 9 after amplified by the laser diode 7. |
