Highly birefringent air-core photonic band-gap fiber free of surface modes

A new type of highly birefringent(HB) air-core photonic band-gap fiber free of surface modes is theoretical investigated by using the full-vector finite element method(FEM). From the simulation result and thorough analysis on the guided mode field distribution, the proposed HB hollow-core photonic band-gap(PBG) fiber is free of surface modes in wider wavelength. The phase-index and group-index birefringence of the HB fiber are studied, which have the value in the order of 10
^-4
and 10
^-3
, respectively.