OPTICAL FIBER PART, METHOD FOR MANUFACTURING OPTICAL FIBER PART AND SEMICONDUCTOR LASER MODULE

摘要

PROBLEM TO BE SOLVED: To provide an optical fiber part by which high optical output is obtained by controlling the reduction of optical output owing to the use of a fiber grating, and clad mode light is effectively utilized for wavelength stabilization of a semiconductor laser module or the like. SOLUTION: In the optical fiber part 1 which is provided with an optical fiber having a core 2 and a clad layer 3 which is former around the core 2 and has a refractive index smaller than that of the core 2, the fiber grating which reflects clad mode light of a prescribed wavelength propagating the clad layer 3 is formed in the clad layer 3. The clad layer 3 is provided with a first layer 5 formed in the outside of the core 2 and a second layer 6 formed in the outside of the first layer 5, and the fiber grating is formed in the second layer 6. The first layer 5 is formed in such a thickness that a laser beam propagating the core 2 does not reach so that the field distribution k of the laser beam propagating the core 2 is substantially zero in the boundary between the first layer 5 and the second layer 6.