Patent ID: 7664157
Filing Date: 2010-02-16
Classification: H01S

Abstract:
1. A tunable laser comprising: a multiple ring resonator comprising a plurality of ring resonators having respective ring-shaped waveguides and respective different optical path lengths, the ring-shaped waveguides having circumferential lengths different from each other, the ring-shaped waveguides being connected in series; a first optical waveguide coupling a first ring resonator to said multiple ring resonator; a single optical input/output device directly coupled to said first optical waveguide, said optical input/output device being a laser diode or a semiconductor optical amplifier adapted to provide a single optical signal to a last ring resonator of the multiple ring resonator; a second optical waveguide coupled to said multiple ring resonator; an optical reflector coupled to said second optical waveguide, said optical reflector removing light at an unwanted wavelength and reflecting light at a required wavelength; at least one third optical waveguide coupling adjacent ring resonators; and a wavelength varying mechanism for changing the resonant wavelength of said multiple ring resonator, wherein a free spectral range (FSR) of each ring resonator is different from one another, and a resonant wavelength changes depending on the circumferential lengths of the ring resonators.