Patent ID: 6529534
Filing Date: 2003-03-04
Classification: H01S

Abstract:
A wavelength controlling circuit controlling a wavelength of a laser signal, comprising:a laser diode module including a semiconductor laser diode, a temperature detection element and a temperature adjustment element; first wavelength controlling means including an optical band-pass filter used as a wavelength discrimination element discriminating the wavelength of the laser signal, adjusting the temperature adjustment element to control the wavelength of the laser signal within a range of fine adjustment within which the wavelength can be discriminated by said optical band-pass filter; and second wavelength controlling means for adjusting the temperature adjustment element, when the wavelength of the laser signal is outside the range within which the wavelength can be discriminated with a wavelength discrimination characteristic by said optical band-pass filter, to adjust the wavelength of the laser signal roughly so that the wavelength may be included in the range within which the wavelength can be discriminated by said optical band-pass filter.