Patent ID: 7197208

Claim:
A wavelength tunable light source, comprising: a resonant light path supporting oscillation of light in at least one longitudinal mode; an optical gain medium disposed in the resonant light path; an optical reflection grating have a reflective grating surface arranged to receive incident light along the light path at an incidence angle relative to the grating surface and to diffract light from the reflective grating surface along the light path at a diffraction angle relative to the grating surface different from the incidence angle; a first acousto-optic deflector arranged to intercept light along the light path, and operable to deflect the intercepted light and to induce a first Doppler shift of longitudinal mode frequencies; and a second acousto-optic deflector arranged to intercept light along the light path, and operable to deflect the intercepted light and to induce a second Doppler shift of longitudinal mode frequencies, wherein the first and second Doppler shifts are in opposite directions.