MANUFACTURING METHOD FOR DISPERSION SHIFTED OPTICAL FIBER INCREASING EFFECTIVE ACTIVE AREA

PURPOSE: A manufacturing method of a base material for a dispersion mobile optical fiber with an extended effective area is provided to obtain an optical fiber in which a zero-dispersion wavelength is in the range of 1480-1500 nm, zero-dispersion slope is 0.05-0.09 ps/nm2*km by manufacturing the base material as a double ring profile through vapor-phase axial deposition (VAD) method. CONSTITUTION: A manufacturing method of a base material for a dispersion mobile optical fiber with an extended effective area comprises following steps: forming a soot deposit for core which has a core and a doubling in an exterior of a seed rod (10) by depositing porous glass corpuscle having a core and a cladding composition on the glass rod, and applying a flame hydrolysis to a frit; removing a OH group by preliminary dehydrating the soot deposit for core in a furnace which has a Cl2 gas atmosphere; vitrifying the soot deposit for core with OH removed group as transparent glass through a first sintering; forming a glass rod for core by elongating a vitrified soot deposit for core to an external diameter of being designed; depositing a soot for the cladding by applying the flame hydrolysis again from outside of the glass rod for core; secondly sintering the soot for the cladding.