Vytran, a supplier of fibre fusion splicing, assembly and fibre-based glass processing solutions, has coherently combined two, three, and four fibre lasers to produce more than 100W of single transverse mode output at around one micron from an all-fibre, all-passive configuration. These results conclude a two year Small Business Innovation Research (SBIR) Phase II contract for the Air Force Research Laboratory (AFRL) Directed Energy Directorate at Kirtland Air Force Base (Albuquerque, New Mexico).
'We have achieved record power levels of over 100W from self-organised beams in two-, three- and four-laser combinations by using large mode area (LMA) 2x2 couplers in all-fibre and all-passive configuration,' said Dr Baishi Wang, Vytran director of technology. 'In addition, we reached 210W by combining four lasers using a LMA 7:1 fibre coupler. This work paves the way for further coherent power scaling to kW level and beyond by combining multiple lasers.'
Coherent beam combining (CBC) is a technique that combines multiple laser emitters, in this case fibre lasers, into a single, higher power, brighter, high-quality beam. This latest demonstration not only advances the output power for all-fibre, all-passive laser beam combination, but it also provides scientists with a better understanding of the underlying mechanisms of self-organised beam combination, especially the role of fibre nonlinearity.
'This demonstration has significantly advanced coherent combined output power compared with previous fibre laser-based CBC attempts and we attribute the results in part to the precision fused fibre components employed in the system,' said Jean-Michel Pelaprat, Vytran president and CEO. 'All of these components were produced with our GPX-3400 glass processor, a unique filament fusion system that is routinely used to manufacture the splices, couplers and combiners critical in high-power fibre lasers.'
Applications for high-power fibre lasers include industrial uses such as metal cutting and welding and material surface treatment along with other applications that require high-power, high-brightness laser output.
Vytran was the primary contractor for the SBIR Phase II grant. Key collaborators also included scientists and engineers at Hughes Research Laboratories in Malibu, California, and Crystal Fibre (NKT Photonics) in Birkerød, Denmark. 'We also thank Anthony Sanchez and his team at AFRL with whom we worked closely on this project,' said Pelaprat.