LIGHT SOURCE DEVICE AND OPTICAL COHERENCE TOMOGRAPHY APPARATUS

A light source device capable of varying a light oscillation wavelength includes a plurality of optical gain media, a dispersing element, and a wavelength selecting element. The optical gain media amplify light, and have gain wavelength bands that partially overlap and different maximum gain wavelengths. The dispersing element is formed of a single element. Each of light beams emitted from the optical gain media is incident on the dispersing element. The dispersing element disperses the light beams emitted from the optical gain media into light beams of different wavelengths. The wavelength selecting element selects a light beam of a predetermined wavelength from the light beams of different wavelengths into which the light beams emitted from the optical gain media are dispersed by the dispersing element. The light source device emits the light beam of the predetermined wavelength selected by the wavelength selecting element.