Abstract

Many experiments are presented in the literature on Raman fibre lasers based on germanosilicate fibres, with power ratings up to 150 W [1-2]. Compared to germanosilicate fibres, phosphosilicate fibres have larger Stokes shift (~1330 cm⁻¹) thereby limiting the number of necessary cascades to reach the desired wavelength and also increasing the conversion efficiency [3-5]. To our knowledge, the maximum power ever reported in literature concerning Raman fibre lasers with phosphosilicate fibre is 13.2 W with an efficiency of 32.5% in 2004 [4]. In this paper, we present an all-in-fibre Raman laser delivering 20.6 W at 1270 nm with an efficiency of 70%. This laser could be applied to medical applications like photodynamic therapy of cancers [5].

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