OPTICAL FIBER COMBINER WITH INTERMEDIATE CLADDING HAVING REFRACTIVE INDEX LESS THAN REFRACTIVE INDEX OF INTERNAL CLADDING, OPTICAL FIBER, AND LASER DEVICE

摘要

The present invention provides an optical fiber combiner capable of controlling the generation of intense heat in an optical fiber combiner and reducing the potential damage to the optical fiber and the optical fiber combiner. The optical fiber combiner according to the present invention includes a plurality of optical fibers. Each optical fiber has a tapered part that includes a core 57, an internal cladding 59 surrounding the core, and an intermediate cladding 62 surrounding the internal cladding 59, and the refractive index of the intermediate cladding 62 is less than the refractive index of the internal cladding 59. The light advancing from the internal cladding 59 to the intermediate cladding 62 is reflected at the boundary surface between the internal cladding 59 and the intermediate cladding 62 when the incidence angle is greater than a critical angle (when the intermediate cladding is viewed from the internal cladding). As such, the strength of light actually entering the intermediate cladding 62 (containing contaminants, dusts and so forth 66) from the internal cladding 59 decreases, thereby controlling the generation of intense heat in the optical fiber combiner.