High-power lasers at the Optoelectronics Research Centre, University of Southampton 　　  

    Johan Nilsson is a Professor at the Optoelectronics Research Centre (ORC), University of Southampton, England. In 1994, he received a doctorate in Engineering Science from the Royal Institute of Technology, Stockholm, Sweden, for research on optical amplification. Since then, he has worked on optical amplifiers and amplification in lightwave systems, optical communications, and guided-wave lasers, first at Samsung Electronics and later at ORC. His research has covered system, fabrication, and materials aspects of guided-wave lasers and amplifiers, and in particular device aspects of high power fiber lasers and erbium-doped fiber amplifiers. He is leading ORC’s high-power fiber laser group which, in recent years, demonstrated a number of world-firsts and world-records in the field, including the first single-mode kW fiber laser and the first cladding-pumped fiber Raman laser. He has published nearly 400 scientific articles and has taught several short courses on fiber lasers and amplifiers. He is a fellow of the OSA, a life member of the SPIE, a consultant to, and co-founder of, SPI Lasers, and a member of the advisory board of the Journal of the Optical Society of Korea. In addition, he was guest editor of two issues on high-power fiber lasers in IEEE Journal of Selected Topics in Quantum Electronics in 2009. He has also been active in the organization of several conferences and meetings, and is a former chair of the Laser Science and Engineering technical group in OSA’s Science and Engineering Council. At present he is a member of the technical program committee of the Europhoton and the Optical Instrument and Technology conference.p>

   After over a decade of rapidly growing output power from high-power fiber lasers, the last few years have seen a lower rate of headline results. The high cost and engineering requirements at the multi-kW level contribute to this, but there are also increasing needs to address limits imposed by nonlinearities, thermal effects, and beam degradation. This often calls for a better understanding of the fundamentals. I will present recent results on the physics and the performance of different fiber lasers in different regimes of operation, and discuss new possible directions. One example is ICAN, which aims at massively parallel beam combination of femtosecond pulses for wakefield acceleration