optical fiber

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Figure 11: The forming of stepped-index optical fibre, using the double-crucible technique. Glass rods containing the core-glass and cladding-glass compositions of the eventual fibre are fed into two concentric platinum crucibles, which are heated in a silica-lined furnace. The two compositions melt under an inert atmosphere and flow through an orifice as a composite, concentric stream, the diameter of which is monitored by a fibre diameter scanner. After passing through primary and secondary polymer coatings and curing ovens (which cure the protective coatings through thermal or ultraviolet energy), the solidified optical fibre is wound around a capstan and onto a take-up reel.

$Figure 12: The preparation of graded-index optical fibre, using the modified chemical vapour deposition (MCVD) technique. A carrier gas of oxygen (O2) is bubbled through liquid silicon tetrachloride (SiCl4), phosphorus trichloride (PoCl3), and germanium tetrachloride (GeCl4). The resulting vapours are mixed in suitable proportions in a flow controller and then fed through a vapour inlet into a silica tube. Heat generated by a traversing oxygen and hydrogen (O2 and H2) torch sets off a vapour phase reaction in which a soot, containing silica as well as oxides of phosphorus and germanium, is deposited in a series of porous layers on the inside of the tube. The layers are dehydrated by gaseous sulfur oxychloride (SOCl2), and various exhaust products are vented through a vapour exhaust. The layers are then sintered, collapsed under vacuum, and condensed to concentric core and cladding layers of the desired refractive properties.$

Follow a sea plow burying a fibre optic cable with repeaters for efficient information transmission

Watch a silica glass preform heated by a furnace be turned into an optical fibre

optical fiber

technology

Also known as: glass fiber

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Last updated

July 1, 2026

Quick Summary

Optical fiber is the science of transmitting data, voice, and images using light through thin, transparent fibers. These fibers are typically made of glass or plastic and are incredibly thin, often with a core diameter as small as 10 micrometers.12

The technology relies on total internal reflection, where light beams bounce within the fiber's core, allowing data to travel long distances with minimal signal loss. This makes optical fiber superior to copper wire for transmitting data over extended ranges.12

Optical fibers are widely used in telecommunications for telephone lines and computer networks. They are also utilized in medical instruments like fiberscopes for endoscopy and for inspecting manufactured products.12

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