| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber preform comprising such a process that a porous clad soot deposited on a core rod is heated externally, and concurrently the lower end of the core rod with no soot deposited thereon is heated separately, thereby heating the soot both externally and internally to effect dehydration and sintering of the soot in a short time. SOLUTION: This method for producing an optical fiber preform comprises the following process: the length of a core rod 1 is set longer by a magnitude of 1, the lengthened portion is left so as not to deposit a porous clad soot 6 thereon, and the porous clad soot 6 is then suspended inside a core pipe 8 with the above portion turned downward; the porous clad soot 6 is then heated with an annular heater 5, and concurrently, the above portion is heated with another heating device 7; thereby the heat applied by heating the lower part of the core rod 1 is transferred through the core rod 1 onto the inner surface of the porous clad soot 6; thus the porous clad soot 6 is heated externally and internally as well, with the result that the time of treating the porous clad soot 6 is shortened and the consumption of expensive helium gas necessary for the treatment is reduced.</p> |
