| 摘要 |
PURPOSE:To improve long term stability and wavelength accuracy of a variable wavelength light source by controlling the transmission wavelength of a Fabry-Perot etalon to the wavelength of the output light of a reference wavelength light source, controlling the output wavelength of a semiconductor laser to one of the transmission wavelength, and moving the output wavelength by a temperature input or a current input. CONSTITUTION:The output light of a reference wavelength light source 1 is periodically varied in a resonator length by a Fabry-Perot etalon 4 according to the modulation signal of an oscillator 8, the intensity of the transmission light is modulated, detected through a polarizing beam splitter 5 by a photodetector 6, fed back to the applied voltage of a piezoelectric element 9, and the peak of any one of the wavelengths of the etalon 4 is controlled to the oscillation wavelength of the light source 1. On the other hand, the output light of a semiconductor laser 10 is isolated by a splitter 5, incident to a photodetector 13, and its oscillation wavelength is controlled by a similar method to one of other transmission wavelength of the etalon 4. If the wavelength control loop of the laser 10 to the variation in the temperature or current input is saturated, it is jumped to the peak of next transmission wavelength, thereby accurately varying the wavelength. |
