A wavelength-variable light source apparatus having a wavelength calibration
function
of emitted light therefrom. The apparatus includes a semiconductor laser light
source section, an external resonance section having a reflection surface for externally
resonating emitted light from the semiconductor laser light source section at a
predetermined reflection wavelength, a drive section for moving a position of the
reflection surface in the external resonance section for varying an external resonance
condition, a control section for controlling a variable move distance of the reflection
surface in the drive section, and a wavelength detection section comprising a gas
cell having a wavelength absorption characteristic absorbing light at a plurality
of specific wavelengths for sweeping light emitted from the external resonance
section into the gas cell and detecting an absorption wavelength of the emitted
light, wherein the control section controls the move distance of the reflection
surface in the drive section based on the absorption wavelength detected by the
wavelength detection section.
