Heraeus synthetic fused silica for optical fibre

What it is

An optical fibre is a glass thread with a core that carries light and a surrounding cladding that keeps it inside. In standard fibre, most of the glass is cladding. Heraeus, through its business now called Heraeus Covantics, makes synthetic fused silica cylinders and tubes from which fibre makers form preforms, the thick glass rods that are heated and drawn into hair-thin fibre.

How it works

Synthetic fused silica is made from chemical precursors rather than melted natural quartz, giving extremely low impurity levels and very low light loss. In the rod-in-cylinder (RIC) process, which dates from 2002, a core rod is inserted into a large fused silica cylinder and the assembly is drawn directly into fibre. Larger cylinders mean longer, uninterrupted draws and lower cost per kilometre.

Why it stands out

• Heraeus says it is the largest manufacturer of synthetic fused silica for telecommunication fibres.
• It says one state-of-the-art preform yields 4,000 kilometres of fibre.
• Around 2012, Heraeus said material from its Bitterfeld plant, opened in 1992, had gone into more than 500 million kilometres of fibre, and was used in about a quarter of all optical fibre made worldwide. These are older company figures.
• Research now targets ultra-low-loss and multicore fibres for higher data rates.

Heraeus also sells ZANDOSIL, a high-purity synthetic amorphous silica supplied as powder, granulate or dispersion, and offers preform manufacturing as a service, producing large preforms that can be drawn for several days without interruption. Heraeus has been involved in the telecom industry since the 1970s.

Where you meet it

In the undersea cables, long-distance links and fibre-to-the-home connections that carry internet traffic, including the backhaul behind every mobile network. Related Heraeus quartz glass products are used in semiconductor fabs, where purity and heat resistance matter.

Sources

• Heraeus: Heraeus Comvance
• Investment and Marketing Corporation Saxony-Anhalt: Covers by the tonne for fibre optics
• SEMI: Heraeus Covantics