By combining the sol-gel method and the spin-coating technique, silica-on-s
ilicon Er-doped glass optical planar waveguides were fabricated. The active
guiding layer consisted of SiO2-TiO2-Er2O3-Yb2O3-Al2O3 and its composition
was optimized by measuring the fluorescence lifetime tau of the I-4(13/2)
metastable level of Er3+ ions. The Er concentration was chosen as the quenc
hing concentration, which was found to be 1.4 x 10(20) ions/cm(3). The Yb c
oncentration was found to have little influence on tau, whereas a concentra
tion of 1.5 x 10(21) ions/cm(3) of AlO3/2 was found to be enough to maximiz
e tau. The 71aluminum concentration barely influenced the flatness of the a
mplified spontaneous emission spectrum. Strip-loaded waveguides were design
ed by reactive ion etching of the cladding layer and their performance as c
andidates for integrated optical amplifiers was assessed, Propagation losse
s of 0.7 dB/cm and loss reduction of 2.7 dB (for a 5.7 cm long waveguide) w
ere measured. (C) 1999 Elsevier Science B.V. All rights reserved.