Skip to content
Material World
Element · Er

Erbium

The element that makes long-distance optical fibre work, by amplifying light without turning it back into electricity.

Optical medium Pigment

Erbium is a lanthanide with an unremarkable metallic form and one property of enormous consequence: erbium ions embedded in glass amplify light at almost exactly the wavelength at which silica fibre is most transparent.

Before that was understood, a long optical link needed the signal converted back to electricity, amplified, and converted again every so often — each conversion a bottleneck and a point of failure. An erbium-doped length of fibre amplifies the light directly, and intercontinental optical communication became a matter of engineering rather than of hope.

Uses

Erbium-doped fibre amplifiers are the dominant use, and they sit in every long-haul optical link and submarine cable. The erbium is a tiny fraction of the glass; the effect is not.

Erbium also colours glass and glazes pink, and erbium lasers are used in dentistry and dermatology because their wavelength is strongly absorbed by water and therefore removes tissue in a very shallow, controllable layer.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

is produced by

  • Rare earth separation — process · a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller

is found in

  • Yttrium aluminium garnet — compound · doped in for a wavelength water absorbs strongly, which is what makes it a surgical and dental instrument
  • Optical fibre — material · in the few metres of doped fibre that make up an amplifier, which is what made long-haul optical communication economic

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • PubChem
    US National Library of Medicine · Mixed — aggregated third-party content, rights retained by depositors

Questions this page answers

Where it comes from, and what it becomes

Follow Erbium back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Erbium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the principal ore of the light rare earths, carrying all of them together) → Bastnäsite
  • Erbium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the other feed alongside bastnäsite, bringing thorium into the residues with it) → Monazite
  • Erbium → is produced by (a heavy rare earth; the separation is the same cascade, run longer because the differences are smaller) → Rare earth separation → takes as input (the heavy rare earth feed, where monazite and bastnäsite bring the light ones) → Xenotime