PREPARATION METHOD OF THE PREFORM FOR A LOW LOSS SINGLE MODE OPTICAL FIBER

摘要

PURPOSE: A method for preparing the preform for a low loss single mode optical fiber is provided, to lower the loss in the range of 1340 to 1460 nm, thereby to broaden the usable wavelength range and to allow the optical fiber to be used in any range between 1280 and 1620 nm. CONSTITUTION: The preform for a low loss single mode optical fiber is prepared by forming a shoot accumulation for a core by flame hydrolyzing a glass source to accumulate a porous glass fine particle of the core and clad composition to a glass load; dehydrating the shoot accumulation for a core in a furnace under the atmosphere containing chlorine gas to remove an OH group; sintering the shoot accumulation to make it be transparent glassed; elongating the glassed shoot accumulation to make a glass rod for a core; flame hydrolyzing the outer portion of the glass rod to accumulate the shoot for a clad; dehydrating the shoot accumulation for a clad in a furnace under the atmosphere containing a chlorine gas to remove an OH group; and sintering the shoot accumulation.