Full-vector improved effective index method for analysis of fiber Bragg gratings formed in photonic crystal fibers

The reflectivity and the Bragg wavelength of a fiber Bragg grating formed in a photonic crystal fiber with central pure core defect and a regular hexagonal array of microscopical holes cladding were investigated by the full vector improved effective index method, the calculated results indicate that the effective index of the FSFM decreases with increasing the filling factor, the reflectivity increases with the filling factor increasing, the Bragg wavelength decreases from 1544.133 nm to 1540.509 nm with the filling factor increasing.