OPTICAL FIBER HAVING LOW AND UNIFORM OPTICAL LOSS ALONG THE ENTIRE LENGTH AND METHOD FOR FABRICATING THE SAME

摘要

A method for producing optical fiber preform capable of producing optical fiber having low and uniform optical attenuation loss along its entire length including :he top end portion is provided. The method comprises carrying out simultaneously sintering and collapsing steps by inserting the dehydrated hollow soot porous body; with predetermined speed in hot zone of the furnace till its top end reaches the hot zone and is left for a predetermined duration thereafter the preform is uplifted for a predetermined length at a predetermined speed to avoid heat loss in the optical)reform and re-inserted in the hot zone of sintering furnace at a predetermined speed and left for predetermined duration to result in formation of the preform having collapsed capillary including at its top end.