Laser light source device and image display device

A laser light source device, comprising:

• a laser light source for emitting an excitation light;
• a laser cavity including a fiber which contains a laser-active substance and on which the excitation light from the laser light source is incident, a first fiber grating provided at a side of the fiber toward the laser light source and having a plurality of reflection peaks, and a second fiber grating provided at a light emission end of the fiber and having a plurality of reflection peaks;
• a wavelength converter for converting a fundamental wave emitted from the laser cavity into a harmonic wave;
• a reflection wavelength varying unit capable of shifting the reflection wavelengths of the reflection peaks of the second fiber grating;
• and
• a controller for controlling the oscillation wavelength of the laser cavity by means of the reflection wavelength varying unit and controlling a phase matching condition of the wavelength converter, wherein
• intervals between adjacent reflection peaks of the first fiber grating are different from those between adjacent reflection peaks of the second fiber grating.