The invention relates to a fusion shrinkage preparation method for preparing a core rod of an
optical fiber preform rod through fusion shrinkage of a doped
quartz liner tube. According to the fusion shrinkage preparation method of the core rod of the
optical fiber preform rod, the deposited doped
quartz liner tube is mounted on a fusion shrinkage lathe. The fusion shrinkage preparation method of the core rod of the
optical fiber preform rod is characterized by comprising the following steps: enabling the doped
quartz liner tube to rotate at a rotation speed being 15-30rad / min, supplying a heat source for fusion shrinkage by taking a
heating furnace sleeve as a heating device, heating at the temperature of 1900 to 2250 DEG C, enabling the
heating furnace sleeve to move forth and back from one end to the other end of an axial liner tube of the doped quartz liner tube, carrying out gradual fusion shrinkage on the doped quartz liner tube and finally firing; and sealing two ends of the doped quartz liner tube and introducing
mixed gas for corroding the inner wall of the liner tube in the fusion shrinkage process. By virtue of the fusion shrinkage preparation method of the core rod of the optical
fiber preform rod, an F-containing compound high in reactivity is taken as the lining
corrosion gas; the fusion shrinkage and
corrosion are carried out synchronously, so that the reduction of a
refractive index of a core layer can be effectively avoided, the time for producing the core rod of the preform rod can be greatly reduced, the
processing efficiency and the efficiency of using the device can be improved, the production cost of the optical
fiber preform rod can be reduced, and the stability of the optical
fiber water peak can be guaranteed, therefore the quality of the optical fiber
processing is improved.