Abstract

Rod-type fibers are the basis for ultra-short pulse fiber laser systems with mJ pulse energies and GW peak powers. The large mode-field diameters in combination with short fiber lengths allow for a radical reduction of parasitic nonlinear effects. Furthermore, shorter fibers are a necessity for more compact commercial systems. We present a concept to shorten the fiber length even further by increasing the refractive index of the cladding allowing for an increase of doping concentration without altering the fiber characteristics. Hence, higher performance and/or smaller device dimensions are feasible. In a first experimental demonstration we have been able to extract >100W average power from 36cm long ytterbium-doped large-pitch fiber possessing a mode-field diameter of 35µm.

© 2013 Optical Society of America