  We examine localized surface modes in the core of a photonic crystal fiber
composed of a finite nonlinear (Kerr) hexagonal waveguide array with a central
defect. Using a discrete approach, we find the fundamental surface mode and its
stability window. We also examine an unstaggered, ring-shaped surface mode and
find that it is always unstable, decaying to the single-site fundamental
surface mode. A continuous model computation reveals that an initial vortex
excitation (S=1) of small amplitude around the central hole can survive for a
relatively long evolution distance. At high amplitudes, however, it decays to a
ring configuration with no well-defined phase structure.
