Zero dispersion wavelength and dispersion slope control of hollow-core photonic bandgap fibres

This paper investigates the zero dispersion wavelength anddispersion slope control of hollow-core photonic bandgap fibres(PBGFs) by using a full-vector finite element method. By simulationwe found that theoretically the zero dispersion wavelength can betailored by respectively changing the rounded diameter of air holes,pitch, refractive index, normalized thickness of core rings, andhole diameter to pitch ratio. At the same time the tailoring ofdispersion slope can also be realized by changing the rounded diameterof air holes or pitch or normalized thickness of core rings. Toillustrate the reasonability of fibre designs, this paper also givesthe variance of normalized interface field intensity which measuresthe scattering loss relatively versus wavelength for differentdesigns. From the viewpoint of loss, varying the rounded diameterand the thickness of core ring could shift zero wavelength but it isdifficult to get the required parameters within so tiny range inpractical drawing of PBGFs, on the other hand, it is possible inpractice to respectively alter the pitch and refractive index toshift zero wavelength. But varying hole diameter to pitch ratio isnot worthwhile because they each induce large increase of loss andnarrowness of transmission bandwidth. The zero dispersion wavelengthcan be engineered by respectively varying the rounded diameter of airholes, pitch, refractive index, and normalized thickness of corerings without incurring large loss penalties.