Patent ID: 7711019
Filing Date: 2010-05-04
Classification: H01S

Abstract:
1. A variable wavelength light source comprising: a gain element forming an output facet of a resonator; a variable wavelength reflector forming a reflection facet of the resonator for selecting a desired resonance wavelength by changing a resonance wavelength of the resonator; a wavelength selective element that selects the resonance wavelength, the wavelength selective element being arranged in the resonator formed between the output facet and the reflection facet; a beam splitter for monitoring an incident light from the gain element and a reflected light from the variable wavelength reflector, the beam splitter being arranged in the resonator; a phase adjustment element that is arranged in the resonator and changes a phase of the resonance wavelength; and a wavelength-lock control unit that locks the resonance wavelength to the desired resonance wavelength by adjusting the phase of the resonance wavelength by the phase adjustment element based on the incident light monitored by the beam splitter and by changing the resonance wavelength by adjusting the variable wavelength reflector based on a ratio between the incident light and the reflected light, wherein the wavelength selective element and the variable wavelength reflector are etalons, the phase adjustment element is an optical phase shifter in which liquid crystal is filled between optical glass plates having transparent electrodes, the variable wavelength reflector has liquid crystal filled in an etalon cavity, and the wavelength-lock control unit changes an effective refractive index of the liquid crystal by changing alternating-current voltage applied to the liquid crystal.