Large mode area fibre designs for micro-machining applications

High power, high-energy, rare-earth-doped fiber laser sources are now considered a suitable option for a number of applications in Medicine, Telecom, LIDAR and industrial applications. Regarding the generation of high-energy pulses, there is a compromise between gain volume and M² value or beam parameter product for the generation of pulses with useful energy content, for the aforementioned applications and good pulse shape and even a Gaussian output. In this paper, we will present a set of large mode area fiber designs along with full optical characterization data will be presented. Results on energy per pulse from 4 to 20KHz repetition rate and up to 1.3mJ energy for a 350um inner cladding LMA fiber will be discussed among other fiber designs. All fibres were made from proprietary procedures and will be employed in micromachining applications such as metal deposition in applications where laser-assisted cold spraying processes are used. A full review of our LMA fibre designs will be presented.