Patent ID: 8331408

Claim:
A fiber laser device comprising: a seed laser light source configured to output seed laser light; a pumping light source configured to output pumping light; an amplification optical fiber to which the seed laser light and the pumping light are input and which is configured to amplify the seed laser light and output the amplified light as laser light, wherein the amplification optical fiber is doped with rare earth elements that are pumped by the pumping light; a wavelength converter to which the laser light output from the amplification optical fiber is input and which is configured to convert a wavelength of light having an intensity equal to or higher than a predetermined intensity; a wavelength selecting filter to which the laser light output from the wavelength converter is input and which is configured to transmit light whose wavelength is converted by the wavelength converter and to suppress transmission of light whose wavelength is not converted by the wavelength converter when light in the same wavelength band as the seed laser light is input to the wavelength converter; an output section configured to output laser light output from the wavelength selecting filter; and a controller configured to control at least the seed laser light source and the pumping light source, wherein the controller controls the seed laser light source and the pumping light source to change from a preliminary pumping state to an output state, in the preliminary pumping state, the seed laser light is not output from the seed laser light source, the pumping light is output from the pumping light source, and the pumping light has such an intensity that the wavelength of light emitted by the pumping light in the amplification optical fiber is not converted by the wavelength converter, and in the output state, the seed laser light is output from the seed laser light source, the pumping light is output from the pumping light source, and the seed laser light and the pumping light have such intensities that the wavelength of the laser light output from the amplification optical fiber is converted by the wavelength converter.