Development of rare-earth-doped large-core photonic bandgap fibre technology for power-scaling at challenging wavelengths

I propose an extensive twelve-month research project on novel generic fibre technology to provide waveguide filtering within rare-earth-doped large-core photonic bandgap fibres. Whilst this technology will enable and improve a wide range of important fibre devices, this proposal will focus on one specific and particularly attractive device, namely, a neodymium-doped large-core photonic bandgap fibre laser operating at around 900 nm generating multi-ten-W average power levels. The goal is to break the current record power level in this spectral range. Further prospective targets include power-scaling to even higher levels, and higher degrees of device work, e.g. the development of an ultrafast-pulse source based on the fibre developed. This proposal takes advantages of the recent impressive results on core area scaling, (of ytterbium-doped fibre sources in particular), increases in brightness of diode pump sources, as well as advances in passive photonic bandgap fibre technology. If successful, this research will lead to compact, efficient and reliable fibre sources that can be used to replace Ti:sapphire lasers in bio-imaging and targeting applications, and after frequency-doubling to the blue, can be used for under-water lidar systems as well as large-scale laser displays. The overall technology outcome related to fibre development can also be extended to other rare-earth-doped fibres, e.g. 980-nm/1178-nm ytterbium-doped fibres or around 1.6-micron erbium/ytterbium co-doped fibres, all of which also suffer from excessive parasitic emissions at 1060~1090 nm and that can be controlled through distributed in-fibre filtering.