Abstract Photonic crystal fibres (PCFs) offer new possibilities of realizing highly birefringent fibres due to a higher intrinsic index contrast compared to conventional fibres. In this paper, we analyse theoretically the modal properties of a kind of polarization-maintaining PCF, namely the elliptical hole photonic crystal fibre (EHPCF) with a central small elliptical hole introduced in the core region. We demonstrate the possibility of achieving large birefringence with zero walk-off in the single-mode regime. This PCF also exhibits unusual dispersion properties. Several hundred nanometres of ultra broadband flattened dispersion near the wavelength 1.55μm is achieved in this EHPCF with a central small hole of dc=0.4$\varLambda$.
Received: 04 September 2003
Revised: 01 March 2004
Accepted manuscript online:
Fund: Project supported by the National High Technology Development Program of China (Grant No 2002AA312190) and the Pandeng Fund of Beijing Jiaotong University (Grant No PD221).
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