Patent ID: 6711183
Filing Date: 2004-03-23
Classification: G02F,H01S

Abstract:
A light source comprising:an optical wavelength conversion device; a wavelength tunable semiconductor laser; a control circuit for controling an oscillation wavelength of light output of the wavelength tunable semiconductor laser; and a second harmonic, optical detector for detecting an output power of a second harmonic wave of the optical wavelength conversion device; wherein; the optical wavelength conversion device includes at least two non-linear optical crystals having substantially the same phase matching conditions and at least one phase adjusting section disposed between the non-linear optical crystals to adjust a phase relationship of a fundamental wave and the second harmonic wave, such that the output power of the second harmonic wave versus wavelength produces an output power characteristic curve having a flat portion near a maximum power of the second harmonic wave; the control circuit controls a driving current of the wavelength tunable semiconductor laser, based on the output power of the second harmonic wave detected by the second harmonic optical detector, so that the oscillation wavelength of the wavelength tunable semiconductor laser is maintained substantially within the flat portion of the output power characteristic of the optical wavelength conversion device; and a bandwidth of the flat portion of the output power characteristic curve is wider than a longitudinal mode interval of the wavelength tunable semiconductor laser.