MANUFACTURE OF OPTICAL TRANSMISSION GLASS PREFORM

摘要

PURPOSE:To manufacture the titled preform doped with much nitrogen by feeding a gaseous silicon compound, NH3 and oxygen or a gaseous oxygen compound into a flame and directly depositing the resulting fine glass powder on a starting member in the molten state. CONSTITUTION:A plasma flame of an inert gas such as He or Ar is sprayed from high frequency plasma torch 2 on thin-walled quartz pipe (starting member) 1 which is moved back and forth while being rotated. On the other hand, a mixed gas of a gaseous silicon compound such as trichlorosilane, NH3 and oxygen or CO2, NO2 or the like is sprayed from nozzle 3 and heated to form glass fine particles represented by formula SiOxNy. The particles are immediately deposited on pipe 1 in the molten state to grow transparent nitrogen-doped quartz glass (SiOxNy) 4.