The last decade has seen fiber lasers, in particular those doped with ytterbium, establish themselves as front runners for many important laser applications such as materials processing. For that, cost, efficiency, and reliability are key requirements. Fiber lasers are able to meet these requirements thanks to their foundation in telecom and the erbium-doped fiber amplifier, as well as to the tight focusing over extended lengths possible with waveguiding devices.
The fundamental properties of a long waveguiding laser, as well as the rapid developments and cost reductions, continue to open up a plethora of opportunities in a wide range of applications. These call for increasingly advanced designs, configurations, and fabrication, to combat re-emerging thermal problems, damage, and photo-darkening to name a few problem areas. I will discuss such applications and how next-generation fiber sources can address these problems through approaches such as improved fiber design and fabrication, phased arrays, and new pumping methods, whilst still retaining advantages in efficiency, cost, and reliability.