Torch fo fabricating optical fiber preform

Abstract From the Canadian patent

A torch for fabricating an optical fiber preform which has a plurality of raw gas injection passages at the center of the torch a plurality of small-diameter combustion supporting gas injection passages independent of each other and disposed to surround the raw gas injection passages on the outer periphery of the raw gas injection passages disposed at the center of the torch and an, annular combustible gas injection passage provided on the periphery of each of the small-diameter combustion supporting gas injection passages. Thus, the torch can stably manufacturing the porous glass preform.