title: Optical-fiber temperature sensor based on upconversion-excited fluorescence.
abstract: The codoping of a heavy-metal fluoride glass by two rare-earth ions, erbium and ytterbium, permits the semiconductor laser infrared excitation of two visible neighboring fluorescence lines of erbium by upconversion, the intensity ratio of which is a single variable function of temperature.
authors.forename: H
authors.initials: H
authors.lastname: Berthou
authors.forename: C K
authors.initials: CK
authors.lastname: Jörgensen