Patent ID: 7620078

Claim:
A tunable semiconductor laser device, comprising: a semiconductor substrate; an active layer that is formed above the semiconductor substrate and that generates light; a wavelength control region that (i) is formed to include the active layer, is (ii) formed in an optical waveguide which guides the light generated by the active layer, and (iii) includes in at least one portion a diffraction grating which selects light having a predetermined wavelength from the light generated by the active layer; a cladding layer formed above the optical waveguide; an insulation film formed above the cladding layer; a first driving electrode formed below the semiconductor substrate; a second driving electrode formed above the cladding layer; a heating portion that is formed above the insulation film and that is used to heat at least one portion of the wavelength control region; a first heating terminal and a second heating terminal that are provided in the heating portion; a first connection line that connects between the second driving electrode and the first heating terminal; and a second connection line that connects between the first driving electrode and the second heating terminal through a power source, wherein current supplied from the power source to the first and second connection lines connected in series through the heating portion is tuned, whereby the wavelength of light emitted to an outside from the optical waveguide can be controlled.