METHOD FOR TUNING SEMICONDUCTOR LASER

摘要

A method for tuning a semiconductor laser including a plurality of wavelength selection portions having cyclic wavelength characteristics, including: controlling a refraction index of the wavelength selection portions; confirming whether wavelength characteristics of the wavelength selection portion caused by the controlling of the refraction index is changed by one cycle or more compared to wavelength characteristics established by a basal value of the refraction index without the controlling of the refraction index; and shifting the refraction index of the wavelength selection portion, of which wavelength characteristics changing is confirmed in the confirming, toward the basal value side by the cycle.