To specify from what part of a fed one preform a certain part of a wire drawn optical fiber is obtained by displaying the side of starting the deposition and growth or/and the side of completion in the resultant optical fiber preform obtained by depositing and growing glass microparticles by a vapor phase axial deposition method.
This optical fiber preform is obtained by blowing SiCl4 and GeCl4 together with an oxyhydrogen flame 2 on the tip of a quartz dummy rod 3 pulled up while being rotated, depositing and growing glass microparticles, producing a porous glass body 1 and locating the starting side in the upper part in a step A, passing the resultant porous glass body 1 through a heating furnace 5, dehydrating and melting the porous glass body 1 and providing an ingot of a dense and transparent optical fiber preform in a step B, passing the preform ingot 6 through a heating furnace 7, pulling the ingot 6 at a higher speed than the feeding speed of the preform ingot 6, carrying out heating and drawing, reducing the diameter and affording an optical fiber preform 10 in a step D, cutting the optical fiber preform 10 to a suitable length, placing a mark M in a part near the top and displaying the side of starting the deposition and growth of the glass microparticles.
YAMAMURA KAZUICHI
SHIMADA TADAKATSU
HIRASAWA HIDEO
Next Patent: PRODUCTION OF OPTICAL FIBER PREFORM AND APPARATUS FOR PRODUCING THE SAME