INFRARED TRANSMITTING OPTICAL FIBER

摘要

PURPOSE:To reduce an emission angle of IR rays released from the end face of an optical fiber and to sharpen condensed beams by adjusting the proportions of crystal mixtures of >=2 kinds of halide crystals different from each other in refractive index so as to gradually decrease the index of the fiber composed of said mixtures from the center radially toward the outside. CONSTITUTION:An IR transmitting optical fiber 1 formed by using a crystal mixture of >=2 kinds of halides different from each other in refractive index is adjusted in the proportion of the mixtures so as to gradually decrease the index from the center of the fiber 1 in the outward radial directions. The core 2 having the same composition and the same index is formed in the central part of the fiber 1, and a clad 3 is formed on the circumference of the core 2 so as to decrease the index gradually and continuously in the outward radial directions. Such a structure enhances performance of condensation of IR rays transmitted through the fiber 1 and reduction of the angle of emission of the IR rays from the end face of the fiber 1. Sharpen condensed beams can be obtained by using an ordinary light condensing optical system, and such beams are used for medical laser scalpels, precise working cutters, etc.