| 摘要 |
PROBLEM TO BE SOLVED: To obtain the light of stable wavelength when the operating condition of a light amplifier is changed and to enable to perform the stable continuous change of wavelength without mode hopping when variable wavelength is performed. SOLUTION: A light amplifier 31 of which both end surfaces are nonreflection treated and which generates natural emission light is used, the light amplifier 31 is operated by a light amplifier operating circuit 32, and the natural emission light emitted from a side surface of the light amplifier 31 is entered to a light resonant reflector B. The light from the light amplifier 31 is conducted to a diffraction grating 35 by a light branching element 34, the reflecting light of the wavelength selected with the angle of incidence from the diffraction grating 35 is conducted to a total reflection mirror 40, so that the resonation between the light of selected wavelength is activated, and the light of resonant wavelength is conducted to the light amplifier 31. With this, stable wavelength with narrow spectrum is obtained with the output light of the light amplifier 31. |
