| 摘要 |
PURPOSE:To maintain the oscillation wavelength constant by compensating for temperature changes depending on the interval of a diffraction grid with the feed back of an electrical signal to the grid corresponding to the deviation in the oscillation wavelength of a laser. CONSTITUTION:A laser beam is radiated from a laser which is adapted to selectively reflect light with by means of a diffraction grid 3 attached to an output guide wave path 2 of a low loss outside a laser activated layer as confined to the wavelength determined by the interval A of the grid. The reflected light is made parallel with a collimation lens 4 and reflected with a mirror 5 to be guided to the spectrometric diffraction grid 6, which diffracts the light in the direction corresponding to the wavelength thereof so that it is focused on a division line of a double split light detector 8 with a lens 7. When the wavelength of the laser is deviated from a specified value, the diffraction direction by the diffraction grid 6 changes causing a difference between two outputs of the detector. The differential output is amplified 9 differntially and after amplified 10 in the voltage, is fed back to an electrode 11 on a diffraction grid for distributory feed back whereby the cycle of the diffraction grid 8 is adjusted to a specified wavelength. This always provide a laser with a constant wavelength regardless of temperature changes. |
