Roughness scattering into substrate radiation modes of rib waveguides

摘要

An estimation of roughness scattering into substrate radiation modes of semiconductor rib waveguides manufactured from III-V compounds is obtained. A guided mode is supposed to be incident upon a corrugated section of the rib sidewall. It is found that scattering into substrate radiation modes considerably exceeds that into slab modes (i.e. surface waves). Once this has been accepted, the radiation formula becomes simple, and should be allowed to replace the less accurate EDC formula.