Bismuth-doped Optical fibres. Advanced Technology and Spectroscopy. – BOATS

Novel approach to the problem of Near Infra-Red (NIR) emission in Bismuth-doped silica glasses is proposed. The core of our technology consists in the use of nano-porous silica xerogels. The xerogels will be doped by conventional solution doping technique with molecular engineered nano-sized dinuclear and heteronuclear Bismuth-containing precursors. The high temperature sintering of doped xerogels results the bulk silica preforms containing predominantly one particular optical centre. Developed in this way Bismuth-doped glasses will be investigated by standard CW and time-resolved optical spectroscopy in a wide temperature range (1.5 - 500K) and by the advanced techniques like pulsed EPR (X- and Q-band) and Optically Detected Magnetic Resonance (ODMR, V-band) at low temperatures. These investigations will allow to establish the energy level diagram for each optical centre of interest (centre in a pure silica sub-network, aluminium-connected and phosphorus-connected) and to clarify the spin multiplicity of the ground and excited state levels. The complete description of electronic states, in turn, should allow the elucidating the nature of the centres responsible for the NIR photoluminescence (PL). Bismuth-doped photonic crystal fibres (PCF) will be developed on the basis of the results of fundamental investigations and studied as the active media for fibre laser applications in three spectral ranges (1100-1200, 1270-1380 and 1410-1470 nm).