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US 7,099,358 B1Granted
Tunable laser light source
AssigneeSantec Corporation
InventorChangho Chong
Life of this patent
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Abstract
A gain medium 12 and a tunable filter are provided in an optical path of laser oscillation. The tunable filter has an optical beam deflector for periodically changing an optical beam at a constant angular speed, a prism 26 on which deflected light is made incident, and a diffraction grating 27. Appropriate selection of the apex angle α of the prism 26 and an angle β formed by the prism 26 and the diffraction grating 27 can provide a tunable laser light source for changing the oscillation frequency at high speed and a constant variation rate.
Claims11
A tunable laser light source comprising:
- an optical path for laser oscillation;
- a gain medium which is provided in the optical path and which has a gain in an oscillating wavelength;
- and
- a tunable optical filter which is arranged in said optical path and which selects a continuously changing wavelength,
- wherein said tunable optical filter comprises:
- an optical beam deflector for periodically deflecting an optical beam over a predetermined rage at a constant angular speed;
- a prism on which light deflected by said optical beam deflector is made incident;
- and
- a diffraction grating on which light emerging from said prism is made incident and which reflects light of a selected wavelength in a direction same as an incidence direction, the selected wavelength changing in accordance with an incidence angle, and
- wherein values of an apex angle α of said prism and an angle β formed by said prism and said diffraction grating are selected so that, when an oscillation frequency is represented as a function f(θ) of an incidence angle θ on said prism, a difference thereof from a linear approximation formula fL(θ) is smaller than that when said prism is not used.
7 more elements
Dependencies are inferred from the claim text.