A zirconium-niobium alloy containing erbium is used as cladding in nuclear reactors. The erbium is a consumable neutron poison: Zirconium And Niobium Alloy Comprising Erbium, Preparation Method And Component Containing Said Alloy (2000).
Erbium oxide is widely used in glass lasers: High Efficiency Erbium Glass Laser (1973).
Broadband signals, carried by fibre optic cables, are amplified by including erbium in the glass fibre: Erbium doped fiber optical amplifier (1991).
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All patent information has been obtained from Espacenet (European Patent Office).