Patent ID: 7463664
Filing Date: 2008-12-09
Classification: G02B,H01S

Abstract:
1. A coherent light source comprising: a wide stripe semiconductor laser capable of exciting a plurality of lateral modes; a mode converter for beam shaping therein light emitted from the semiconductor laser and for controlling the lateral modes; a single-mode waveguide to which the light from the semiconductor laser is coupled through the mode converter; and a wavelength selecting filter through which light exciting an end face of the single-mode wavelength passes, and through which a portion of the light transmitted by the single-mode waveguide simultaneously undergoes wavelength selection and mode selection and is fed back to an active layer of the semiconductor laser using the same exit path, wherein an oscillation mode of the semiconductor laser is limited by the light that has been fed back, so that the semiconductor laser oscillates in a generally single longitudinal mode and generally single lateral mode, wherein the portion of the light coupled to the single-mode waveguide is also reflected at the end face of the single-mode waveguide and fed back to the active layer of the semiconductor laser, and wherein the single-mode waveguide is composed of a nonlinear optical material and has a periodic polarization inversion structure, and a portion of the light from the semiconductor laser is subjected to wavelength conversion by the polarization inversion structure; wherein an oscillation wavelength of the semiconductor laser is fixed such that [n