Rotation
Hollow glass tubes, which typically are made from silica, are put onto a lathe, which slowly rotates.
Gas Injection
Gases like oxygen are introduced into the glass tube. This is done by injecting the gases into the end of the tube. The gases that are introduced have a direct impact on the final fiber optic properties of the cable, so the choice of gas introduced into the tube is important.
Heating
A heating burner (torch) is used to heat up the gases in the tube. The average temperature reached by the gases is around 3,000 degrees F. At this temperature, oxygen in the tube reacts with the tetrachlorides also in the tube, which results in the formation of germania or silica particles.
Soot
Oxide particles in the tube form large chains, which then deposit on the inside wall of the tube because of the pressure and temperature differences between the core of the tube and the outside air.
Torch Reversal
If the torch is kept only on one spot of the tube, the particle distribution is uneven as the oxide particles form their deposits. To avoid this and to get even particle distribution, the torch is moved to the other end of the tube.
Particles Melted
The torch is brought back into the original position, and the deposited particles are heated until they melt. This forms a solid layer of particles inside the tube, and the process then is repeated.
Stretching
The fiber is placed into a special machine that stretches it out into very thin cable.
Coating
A coating is placed over the fiber to protect it. The coating usually is acrylate.
Tags: into tube, introduced into, particle distribution
