Method for manufacturing optical fiber preform

Abstract

An optical fiber base material 4 is produced by inserting a glass rod 2 for core or for core and clad into a glass pipe 1 for clad, decreasing the pressure in the glass pipe 1 while heating it by a heater 3, and performing simultaneous integration and stretching of the glass pipe 1 and glass rod 2. At this time, the integration of the glass pipe 1 and glass rod 2 is effected with a tension longitudinally imparted to the glass rod 2 as by setting the feed speed VR of the glass rod 2 at a value lower than the feed speed VP of the glass pipe 1.

Description

technical field [0001] The present invention relates to a manufacturing method of an optical fiber base material, which is to insert a glass rod for the core wire or a glass rod for the core wire and a glass rod for the cladding into a glass tube for cladding, heat both of them on the one hand, and face the glass tube on the other hand. The decompression treatment was performed, and the above-mentioned integration of the glass tube and the glass rod was carried out simultaneously with the stretching operation. Background technique [0002] The manufacturing methods of optical fiber base material mainly include OVD (outside vapor deposition) method, VAD (axial vapor deposition) method and MCVD (modified chemical vapor deposition) method. In the VAD method and the MCVD method, from the viewpoint of productivity, after the core wire or the glass rod for the core wire and the cladding is manufactured, other processes are used to make the cladding, which accounts for most of the ...

AI Technical Summary

Problems solved by technology

Once the relative position of the glass tube and the glass rod is shifted, the offset will increase as the integration of the glass tube and the glass rod proceeds.

Images