Energy transfer and enhanced 1.54 ?m emission in erbium-ytterbium disilicate thin films

alpha-(Yb1-xErx)2Si2O7 thin films on Si substrates were synthesizedby magnetron co-sputtering. The optical emission from Er3+ ions has been extensively investigated, evidencing the very efficient role of Yb-Er coupling. The energy-transfer coefficient was evaluated for an extendedrange of Er content (between 0.2 and 16.5 at.%) reaching a maximum value of 2×10-16 cm-3s-1. The highest photoluminescence emission at 1535 nm isobtained as a result of the best compromise between the number of Ybdonors (16.4 at.%) and Er acceptors (1.6 at.%), for which a high populationof the first excited state is reached. These results are very promising for therealization of 1.54 ?m optical amplifiers on a Si platform.