The TM mode in the self‐focusing dielectric planar waveguide

The TM 0 guided mode in the self‐focusing dielectric planar waveguide and its universal dispersion curves are obtained by an approximation method, The single mode propagation condition of the fundamental mode TE 0 in the self‐focusing planar waveguide is discussed based on the cutoff wavelengths of the higher‐order TE modes and the higher‐order TM modes. The coupling between the fundamental mode TE 0 and the second mode TM 0 is described by the calculation of the birefringence between the TE 0 mode and the TM 0 mode. It was found that the Kerr effect with α > 0 (α is a parameter which describes the film nonlinearity) causes the fields to be confined in the self‐focusing film, which results in the waveguide wavelength decreasing and the cutoff wavelength increasing as α is increased. In addition, the range of the single mode propagation is increased as α is increased. If the self‐focusing planar waveguide can support both the TE 0 mode and the TM 0 mode, then the coupling between the TE 0 mode and the TM 0 mode is very strong and can be decreased by increasing α. © 1992 John Wiley & Sons, Inc.