Integrated optical amplifiers and microspherical lasers based on erbium-doped oxide glasses

Er3+-doped glasses have been a subject of great interest in the recent years for their application in the areas of guided wave optical amplifiers and lasers. Oxide-glass matrices, in particular, offer the advantage of relatively simple fabrication processes-both for bulk glasses and optical fibers-and have demonstrated quite good properties in the 1.5 μm wavelength band. Here we present some results we have obtained in the development of different silica-based glasses and in their application to the production of integrated optical amplifiers and microspherical lasers. As to the former application, two classes of silica glasses have been produced and investigated, namely a melted soda-lime-alumino-silicate glass and a sol-gel silica-hafnia glass. Both of them exhibit a wide emission bandwidth and seem quite promising for broadband optical amplifiers. We also demonstrated low-threshold microlasers, based on whispering gallery mode spherical resonators, fabricated in different oxide glasses.