Patent ID: 8665916
Filing Date: 2014-03-04
Classification: G02B,H01S

Abstract:
1. A fiber laser comprising: an input double-clad fiber containing high-reflection FBG; an oscillation double-clad fiber doped with a rare earth element; and an output double-clad fiber containing low-reflection FBG, wherein, at both ends of the oscillation double-clad fiber, the input double-clad fiber and the output double-clad fiber are connected so as to structure a laser resonator formed of the oscillation double-clad fiber disposed between the high-reflection FBG and the low-reflection FBG, the output double-clad fiber having: wherein, a high refractive-index resin coat section recoated with high refractive-index resin whose refractive index is the same as a refractive index of the second clad or greater is disposed at a part where the second clad is partly removed between an output end and the low-reflection FBG of the output double-clad fiber, and the refractive index of the high refractive-index resin coat section gradually increases along a direction in which light travels through the first clad.