| 摘要 |
PURPOSE:To uniformize the unevennesses on the surface of porous glass matrix and to obtain the matrix for a large-sized optical fiber preform with good productivity by arranging a plurality of pieces of burners in the equiintervals at the same design dimension and successively transferring and dispersing the starting position of reciprocating movement in the case of producing the matrix for the optical fiber preform by an externally fitting method. CONSTITUTION:In a method for producing the matrix for an optical fiber preform by introducing a gaseous glass raw material 6 into an oxyhydrogen flame burner 2 and blowing glass fine particles produced by flame hydrolysis thereof on the outer circumference of a glass rod 1 for a core being rotated and relatively reciprocating and moving the burner 2 or the glass rod 1 parallel to the axial direction and thereby laminating the glass fine particles one layer by one layer on the glass rod 1 for the core to form the porous glass matrix 8 and then heating and dehydrating this matrix 8 to transparently vitrifying it, the following means is adopted. In other words, at least three pieces of burners 2... having the same dimension are arranged oppositely to the glass rod 1 for the core in the specified euqiintervals in a range over the whole length thereof. The glass fine particles are deposited while successively transferring and dispersing the starting position of the reciprocating movement in at least three points. |
