Patent ID: 7099358
Filing Date: 2006-08-29
Classification: H01S

Abstract:
1. 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 f