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.

Although it is difficult to predict the commercial outlook for the Nd-doped large-core all-solid PBFs to be developed at this early stage, they should be of great immediate and potential impact to a wide and diverse range of academia and industry who are invariably seeking laser sources operating in new spectral ranges. The techniques and fabrication processes developed will also be applicable to other types of doped fibres that require spectral waveguide filtering, e.g. 980-nm or 1178-nm Yb fibres, ~1.6-micron Er/Yb fibres, etc. In this respect, the generic impact of the technology cannot be overstated. In particular, it is highlighted that if the fibre developed through the project is used for a compact and powerful ultrafast source at 900 nm, this could have a great economic impact on the laser industry and market as it represents an immediate replacement for traditional bulk solid-state Ti:sapphire lasers that are widely used for many scientific research fields and uses, including bio-medical applications. To facilitate the realisation of the aforementioned impact various appropriate steps will be taken, including immediate dissemination and intellectual-property licensing as well as exploitation of the outcome of the proposed research through interdisciplinary collaborations, e.g. with university-based bio-medical and oceanography departments, as well as commercialisation through the ORC's established links with companies, such as SPI Lasers (ORC's spin-off), Fibercore, Qinetiq, Sharp Europe, SELEX, BAe Systems, etc. (See more details in the attached Impact plan.)