Waveguide characteristics of planar dielectric heterostructures

Approximate formulas are obtained for the relative differences between the various characteristics of TE and TM modes guided in three-layer planar dielectric waveguides with small discontinuities of the real parts of the permittivities at the interfaces between the media. An analysis is made of the waveguide parameters of the TE modes and of the relative difference parameters of the orthogonal modes in some limiting cases. Some conclusions are drawn from the difference between the gains of the TE and TM modes in a heterojunction laser.