Wavelength-changeable light source capable of changing wavelength of output light, optical communication network using the same and wavelength control method for controlling wavelength of output light of the same

摘要

In a wavelength-changeable light source of the present invention, a wavelength control is performed using a plurality of control systems when the wavelength of a laser, particularly a semiconductor laser, is to be controlled. Wavelength control characteristics of the respective control systems are different from each other, and the wavelength control can be flexibly carried out by combining those characteristics. Specifically, one of the plural control systems is a current control unit for controlling a current supplied to the semiconductor laser and another thereof is a temperature control unit for controlling temperature of the semiconductor laser. In the structure, the wavelength shift with a speedy response time, which can be attained in a wavelength-changeable range obtainable by the current control, can be carried out over a wide wavelength-changeable range obtainable by the temperature control.