Photon-avalanche upconversion of red light into blue light in a thulium-doped fluorozirconate fiber

Summary form only given. We have observed for the first time to our knowledge avalanche upconversion in Tm:ZBLAN fiber. The excitation spectra show that this allows new pumping wavelengths for obtaining blue emission. We aim to test the possible laser performance of an avalanche-pumped Tm:ZBLAN fiber and to investigate other pumping wavelengths that may give an avalanche effect and which may be more conveniently available than those which rely on ground-state absorption.