A PERTURBATIVE APPROACH TO THE STUDY OF PROPAGATION AND ATTENUATION CHARACTERISTICS OF A 5-LAYER PLANAR WAVE-GUIDE

Attenuation properties of five-layer planar waveguides are analyticall y investigated, using a simple perturbation approach. The effect of an additional fifth layer on a four-layer planar waveguide is estimated in respect of the attenuation behaviour as well as the change in the e ffective refractive index. It is found that the attenuation parameter of a four-layer structure is only slightly affected by the inclusion o f a fifth layer. However, the guiding capacity of the structure is inf luenced in a more pronounced way.