Abstract

Fibre technology has improved the compactness, stability and versatility of laser systems. Most of applications need a spatially coherent beam and therefore single-mode fibres are mandatory. Nevertheless the intensity profile of theses fibres usually has a Gaussian-like shape. For some applications, this profile must be transformed to exhibit a ‘top-hat’ intensity profile. Different techniques already exist to get such a profile [1], but with strong drawbacks: losses, alignment difficulties or spatial incoherence. To overcome these difficulties, an elegant and efficient solution is to achieve a single-mode fibre which directly delivers a spatially coherent ‘top-hat’ beam. In fact, microstructured optical fibre technology provides a powerful means to develop a large-mode-area fibre with top-hat fundamental mode profile. Accordingly, we have designed, realized and characterized low-losses large mode area microstructured fibres delivering a top-hat beam [2].

© 2013 IEEE