• Anders, Krzysztof Paweł
• Piramidowicz, Ryszard
• Osuch, Tomasz
• Komorowski, Paweł
• Zdulska, Urszula
• Markowski, Konrad

Abstract

Recent years observed continuous development of compact, low-cost, coherent light sources operating within visible spectral range, driven by numerous applications in optical data processing and storage, photolithography, imaging techniques, medical diagnosis/therapy and many others. At present the market is dominated by wide bandgap semiconductor lasers and diode pumped solid state lasers with frequency conversion. It should be noted, however, that less popular fiber lasers, based on low-phonon energy glasses doped with rare earth ions seem to be an interesting and not fully explored alternative, which could potentially offer higher output powers and better beam quality. In particular, Er3+ doped ZBLAN (53ZrF4+20BaF2+4LaF3+3AlF3+20NaF) glass fibers are continuously considered as a promising active media enabling efficient coherent emission within green spectral range. Rich structure of energy levels of erbium offers relative simplicity of excitation using commercially available laser diodes, while low phonon ZBLAN matrix provides longer fluorescence lifetimes of metastable levels.Main aim of this work was to develop an all-fiber green laser in a new, hybrid geometry, based on combination of Er:ZBLAN active fiber and silica fiber-based passive components of optical resonator and deploying fiber Bragg gratings (FBGs) as highly selective mirrors for green spectral range. The scope of work covered spectroscopic characterization of Er:ZBLAN bulk and fiber samples, identification of processes responsible for emission in green spectral range, determination of a key spectroscopic parameters, development of the numerical model, modelling the lasing properties of Er:ZBLAN, followed by design and optimization of fiber laser in a hybrid configuration.Designing of a final device required solving of two main technical problems – providing an efficient and stable interface between ZBLAN and silica fibers as well as manufacturing FBG mirrors optimized for operation in green spectral range. Both were successfully managed. Glued splice technique has been developed and optimized, finally enabling relatively low-loss (below 2.5 dB) splice between fibers differing in thermo-mechanical and geometrical properties. Also phase mask technique of manufacturing FBGs for green spectral range was mastered and the first gratings have been manufactured, enabling lasing experiments, results of which will be presented at the conference.

Topics

• impedance spectroscopy
• phase
• experiment
• glass
• semiconductor
• glass
• laser emission spectroscopy
• Erbium