The measurements of the wavelength dependence of beam divergence of a photonic crystal fiber (PCF) over the wavelength range 450-950 nm are presented. Results show that the divergence is proportional to wavelength at short wavelengths and flattens at longer wavelengths and are in good quantitative agreement with the predictions obtained by substitution of the results of the published effective-index model into standard expressions for step-index fibers. The results demonstrate that a scalar-wave analysis gives a good approximation to actual properties of the photonic crystal cladding and that treatment of PCF as a step-index fiber with constant core diameter agrees well with experimentally measurement.
|Number of pages||3|
|Publication status||Published - 1 Aug 1999|