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

G.C Righini,S Pelli,P Feron,S Berneschi,C Siligardi,H Portales,M Ferrari,C Arnaud,A Speghini,M Montagna,G Nunzi Conti,M Bettinelli,M Brenci,A Chiasera,L Zampedri

doi:10.1016/j.optmat.2004.11.041

Abstract

Abstract Er 3+ -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.

Highlights

The possibility of confining light inside guiding films and structures has opened new perspectives in the very broad area of passive and active optical components for either telecom or sensing systems
Reference will be made to (a) planar optical waveguides, fabricated in erbium-doped silica glasses, that appear quite promising for the development of broadband integrated optical amplifiers, and (b) dielectric spherical microresonators, where the light is guided through whispering-gallery modes (WGMs), that allowed us to demonstrate low-threshold microlasers
For what concerns the development of Er3+-doped waveguide amplifiers (EDWAs), we have focused our attention on silica-based glasses in virtue of their good chemical durability and adaptability to different waveguide fabrication process

Summary

Introduction

The possibility of confining light inside guiding films and structures has opened new perspectives in the very broad area of passive and active optical components for either telecom or sensing systems. Reference will be made to (a) planar optical waveguides, fabricated in erbium-doped silica glasses, that appear quite promising for the development of broadband integrated optical amplifiers, and (b) dielectric spherical microresonators, where the light is guided through whispering-gallery modes (WGMs), that allowed us to demonstrate low-threshold microlasers. A net optical gain of 1.5 dB/ cm was demonstrated in Er3+/Yb3+ co-doped sodalime–silicate glasses [1,2]. Their performance, was limited by the relatively narrow fluorescence bandwidth, the full width half maximum (FWHM) value being around 17 nm. A second approach has concerned the use of sol–gel-derived silica–hafnia films, that represent an innovative binary glass system with valuable optical, spectroscopic and structural characteristics [5]. We report on the spectroscopic properties of these two glass systems, and on the characteristics of the corresponding optical waveguides

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Results

Conclusion