Patent ID: 6603600
Filing Date: 2003-08-05
Classification: H01S

Abstract:
Apparatus comprising, comprising:an optical fiber configured to convert a first optical pulse received from a laser into a second optical pulse, said first optical pulse having a first bandwidth, said second optical pulse having a continuous wavelength-spectrum extending over a second bandwidth, said second bandwidth being at least about 20 times greater than said first bandwidth; an optical system arranged to receive said second pulse, select a portion of said continuous spectrum of said second pulse and convert said selected-spectrum portion of said second pulse to a third optical pulse having a center wavelength within said selected spectrum portion and having a duration longer than the duration of said second optical pulse; said optical system including a diffraction grating and is configured such that said second pulse is incident at an angle on said diffraction grating and is diffracted from said diffraction grating, with different wavelengths of said continuous spectrum of said second pulse being diffracted from said diffraction grating at different angles, and said optical system being further configured such that those diffracted wavelengths within the selected spectral portion are recombined on a common path by said diffraction grating after following paths of different lengths through said optical system with the path-length of said different paths being inversely related to the wavelength, said recombined wavelengths forming said third pulse; and wherein said diffraction grating is rotatable for selectively varying said incidence angle of said second pulse thereon, and wherein selectively varying said incidence angle selectively varies the spectral portion selected by said optical system thereby selectively varying the center wavelength of said third pulse.