SINGLE MODE OPTICAL FIBER AND METHOD FOR MANUFACTURING ITS PREFORM

摘要

PROBLEM TO BE SOLVED: To provide a single mode optical fiber which is not disconnected in a manufacturing process, has an excellent dispersion characteristic and high quality and is homogeneous. SOLUTION: The single mode optical fiber 1 is formed by enclosing the outer periphery of a glass core 2 having a refractive index greater proportionate to the concentration of a refractive index increasable doping agent with a glass clad 3 having a small refractive index and has an area B having the refractive index smaller than the refractive index of a peripheral area C and a central area A between the peripheral area C and central area A of the core 2.