Realistic monomode air-core honeycomb photonic bandgap fiber with pockets

We present a photonic bandgap calculation of monomode air-core fibers with a realistic treatment of "pocket" interstitials that are formed in a honeycomb cladding. The analytic Fourier transformations of different honeycomb-lattice unit cells are used for plane-wave calculations. The consideration of the true pocket geometry within the cladding shifts the fundamental bandgap to higher frequencies and leads to a hollow-core fiber. The core radius necessary for a monomode fiber is approximated and then proved via the full-vectorial solution. The field distribution and polarization state of the fundamental mode for a real honeycomb photonic-crystal fiber (PCF) are given.