Tunable optical source for producing a coherent optical beam with a wide range of wavelength tuning.

摘要

A tunable laser diode comprises a first reflector (200a), a second reflector (200b), an optical cavity (31- 34) extending between the first reflector and the second reflector for establishing an optical resonance by transmitting an optical beam therethrough, and a gain region (31, 32) for amplifying the optical beam. The optical cavity comprises a first waveguide part (31) connected to the first reflector and extending toward the second reflector, a second waveguide part (32) connected to the second reflector and extending toward the first reflector, a third waveguide part (33) connecting the first waveguide part and the second waveguide part with each other for passing a first optical beam between the first and second reflectors, and a fourth waveguide part (34) connecting the first waveguide part and the second waveguide part for passing a second optical beam between the first and second reflectors, wherein the first waveguide part, the second waveguide part and the third waveguide part form a first optical path having a first optical path length while the first waveguide part, the second waveguide part and the fourth waveguide part form a second optical path having a second optical path length that is different from said first optical path length. In correspondence to the third and fourth waveguide parts, a refractive index modulator (251, 252, 63, 64) is provided for changing a refractive index of the third waveguide part and the fourth waveguide part relatively with each other.