MOPA light source
The present invention relates to a MOPA light source capable of obtaining pulse output by wavelength-conversion of pulse light of fundamental light wave using a simple configuration, and suppressing optical output using a simple method when processing is not performed. The fundamental light wave outputted from a seed light source is amplified in an optical amplification fiber. The amplified fundamental light wave is inputted to one end of a passive optical fiber, and propagates in the passive optical fiber. In the passive optical fiber, stimulated Raman scattering occurs upon propagation of the fundamental light wave. The light of fundamental light wave and light of stimulated Raman-scattered components are outputted from the other end of the passive optical fiber. The light outputted from the passive optical fiber is collimated by a lens, and is then inputted to a branching filter. The light inputted to the branching filter is wavelength-separated into light of stimulated Raman-scattered components having wavelengths longer than that of the fundamental light wave, and light having wavelengths equal to or less than that of the fundamental light wave.
1. A MOPA light source, comprising:
a seed light source generating pulsed light serving as fundamental light wave;
an optical fiber amplifier section amplifying the fundamental light wave outputted from the seed light source;
a passive optical fiber propagating the fundamental light wave amplified by the optical fiber amplifier section, and generating stimulated Raman scattering upon the propagation of the fundamental light wave; and
a branching filter wavelength-separating light of stimulated Raman-scattered components, each having a wavelength longer than that of the fundamental light wave, from light outputted from the passive optical fiber, the branching filter having an output port which principally outputs the light of stimulated Raman-scattered components.
2. A MOPA light source according to claim 1 , further comprising a controller controlling the seed light source such that the seed light source outputs pulsed light or CW light.
3. A MOPA light source according to claim 1 , wherein a suppression ratio of the fundamental light wave at the output port of the branching filter is 1/10 or lower.
4. A MOPA light source according to claim 1 , wherein a light entrance face of the branching filter is inclined by 3° or more with respect to a direction perpendicular to an optical path of light inputted to the light entrance face.
5. A MOPA light source according to claim 1 , wherein the seed light source includes an optical amplification waveguide doped with a rare earth element, and amplified light of the fundamental light wave is generated in the optical amplification waveguide.
6. A MOPA light source according to claim 1 , wherein the wavelength of the fundamental light wave is in the 1.06 μm band.
7. A MOPA light source according to claim 1 , wherein the seed light source is set such that a duty ratio becomes 1/1000 or higher and 1/500 or lower.