PROPERTIES OF PHASE SHIFT DEFECTS IN ONE-DIMENSIONAL RUGATE PHOTONIC STRUCTURES

We theoretically investigated optical properties of phase shift defects in onedimensional rugate photonic structures at oblique incidence. Transmission spectra and energy density distributions of such continuous gradient-index structures with phase shift defects were numerically calculated for TE and TM waves using the propagation matrix method. The study shows that when the angle of incidence increases, (1) the wavelength of the defect mode shifts to a shorter wavelength, (2) the full width at half maximum (FWHM) of the defect mode decreases for TE wave but it increases for TM wave, (3) the stop band of the rugate structure moves toward a shorter wavelength region, (4) the bandwidth is enlarged for TE wave, but it is shortened for TM wave, (5) the peak energy density increases and then drops for TE wave, while it always decreases for TM wave. The effect of number of periods of rugate structures on the energy density distribution was also examined.