Rare-Earth Ion Shows Promise as Gain Media for Integrated Photonics . LAUSANNE, Switzerland, June 21, 2022 — Researchers at ?cole polytechnique fédérale de Lausanne (EPFL), led by professor Tobias J. Kippenberg, fabricated an erbium-doped waveguide amplifier on a compact photonic chip using erbium ion implantation and a silicon nitride (Si 3 N 4 ) photonic integrated circuit (PIC). The waveguide length of the amplifier is up to 0.5 m on a millimeter-scale footprint. ...