In this paper, we present recent results concerning germanium doped highly non-linear photonic crystal fibres (HNLPCF). The finite element method is used to predict main fibre properties. The polarization behaviour of HNL-PCF is discussed in the case of disturbed numerical profiles and real fibres. Characteristics of an optimized germanium doped HNL-PCF are presented and future prospects for in-device integration are discussed as conclusion.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.