Abstract

Cladding pumping of fibre lasers is generating much interest as a route to high output power with the attraction of a geometry allowing simple thermal management. The waveguiding properties of the core can be easily tailored to ensure a single-spatial-mode output free from the problem of thermal lensing which has hindered brightness-scaling in conventional ‘bulk’ solid-state laser sources. Output powers from fibre lasers are however ultimately limited by damage to the core due to its small size. There is limited scope for increasing the core size whilst maintaining good output beam quality and immunity from thermal effects. One attractive solution is to use multiple fibres and wavelength-combine their outputs using an intracavity diffraction grating. This technique, recently applied to Yb-doped fibre lasers to produce 223mW of output power at −1μm [1], exploits the large gain bandwidths that are typical for glass hosts. Thus, this scheme offers the potential for scaling fibre laser powers to much higher levels than have been reported hitherto.

© 2001 EPS