Patent ID: 6885682

Claim:
A fiber laser device comprising: an excitation light source; a first optical fiber having a first end to which output light from the excitation light source is input, and a second end from which the output light is output; a first mirror provided on the second end of the first optical fiber, which allows light incident from the first optical fiber to pass therethrough from a first side of the first mirror to a second side of the first mirror and which reflects light having a first predetermined wavelength incident on the second side; a second optical fiber having a core to which a laser activation material is added, and a first end to which light which passed through the first mirror and light reflected by the first mirror are input, the first end being in contact with the first mirror; a third optical fiber having a first end and a second end; and a second mirror provided on the first end of the third optical fiber, which reflects light having the first predetermined wavelength incident from the second optical fiber and which allows light having a second predetermined wavelength incident from the second optical fiber to pass therethrough, wherein the second optical fiber is longer than the first and third optical fibers, and the first and second ends of the second optical fiber are connected, respectively, to the first and second mirrors, and wherein only the second optical fiber has a core to which a laser activation material is added.