Strong broad C-band room-temperature photoluminescence in amorphous Er2O3 film

Photoluminescence with the bandwidth of 45nm (1523–1568nm at the level of 3dB) was observed in amorphous Er2O3 films grown on quartz substrate by pulsed laser ablation of erbium oxide stoichiometric target. Optical transmission spectrum has been fitted to Swanepoel formula [J. Phys. E 16, 1214 (1983)] to determine dispersion of refractive index and to extract resonance absorption peaks at 980 and 1535nm. The maximum gain coefficient as high as 800dB∕cm at 1535nm was estimated using McCumber theory and experimental spectrum of the resonance absorption. For 5mm long waveguide amplifier with erbium doping confinement factor of 0.1, the theory predicts the spectral gain of 18dB with 1.2dB peak-to-peak flatness in the bandwidth of 31nm (1532–1563nm) when 73% of Er3+ ions are excited from the ground state to the I13∕24 laser level. Strong broadband photoluminescence at room temperature and inherently flat spectral gain promise Er2O3 films for ultrashort high-gain optical waveguide amplifiers and integrated light circuits.