METHOD FOR CONTROLLING DISPERSION OF CLADDING MODE OF OPTICAL FIBER

PURPOSE: A method for controlling dispersion of a cladding mode of an optical fiber is provided to control dispersion of a cladding mode of an optical fiber by adding a transition metal such as Cr or V to a cladding area as well as Ge to the core of an optical fiber by CVD(chemical vapor deposition) process. CONSTITUTION: On cladding an optical fiber, 400-450CCM(standard cubic centimeter per minute) of SiCl4, 80-100SCCM of POCl3 and 50-10SCCM of CF4 are deposited at a temperature of 1900-2000deg.C through MCVD(modified CVD). In a core, 100-150SCCM of SiCl4 and 65-95SCCM of GeCl4 are added to deposit a soot layer at a temperature of 1600-1700deg.C. A transition metal such as Cr or V added to control dispersion of cladding is added by solution doping. The solution is a mixture of 250ml of alcohol having a higher purity than 99.99% and the Cr or V having a density of 1000-5000ppm wherein the alcohol has a density of 6000-9000ppm.