Comparison of Losses in imperfect surface-diffused and buried optical waveguides

Abstract

Theoretical expressions for the scattering losses caused by surface imperfections in both buried guiding layers with a cosh(-2) (x/d) index distribution and surface-diffused waveguides with an exponential profile are presented. Theoretical comparison of radiation losses in buried, surface-diffused, and uniform abrupt guides indicates that, in general, buried layers have lower losses, in agreement with experimental evidence.