JPS6474789A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To control the oscillation wavelength of a semiconductor laser in accuracy of 2Angstrom or less by operating a temperature control element, to which the semiconductor laser is fused, by using a detecting signal in a monitor photodetecting section composed of a wavelength dispersion element and a photodetector to which a plurality of photodetectors are arranged. CONSTITUTION:The rear output beams of a semiconductor laser 11 are reflected by a diffraction grating 17 on a pedestal 18, and converted into an electric signal by a photodetector 19 to which a plurality of minute photodetectors such as a charge- coupled device are disposed. Since the angles of diffraction differ according to wavelength in the rear output beams of the semiconductor laser 11 reflected by the diffraction grating 17, the position of irradiation on the photodetector 19 is varied in response to the change of the oscillation wavelength of the semiconductor laser 11. Consequently, the temperature of a Peltier element 13 is controlled by the transmission signal of the photodetector 19, thus controlling the oscillation wavelength of the semiconductor laser 11. When the diffraction grating 17 having resolution of 10<5> or more and the photodetector 19 with a detecting element in 100mum or less are used, the oscillation wavelength of the semiconductor laser can be controlled in wavelength accuracy of approximately 2Angstrom or less.