Spectral macro-bending loss considerations for photonic crystal fibres

Abstract

Both a scalar method and a fully vectorial method have been applied to modelling the bending losses in photonic crystal fibres (PCFs). Due to a decreasing index difference between the core and the cladding towards short wavelengths, an unusual loss mechanism is seen, that is a short-wavelength loss edge. This is verified by measurements. For large-mode area PCFs, the model gives a massive overestimate, never an underestimate.