Scattering of optical guided waves by waveguide surface roughness: a three-dimensional treatment

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Surface roughness in optical waveguides causes scattering of guided waves, affecting device performance.
• Understanding this scattering is crucial for designing efficient optical devices.

Purpose of the Study:

• To analyze the three-dimensional scattering of optical guided waves by waveguide surface roughness.
• To develop practical formulas for radiated power from TE guided waves.

Main Methods:

• Analysis of scattered fields by satisfying boundary conditions to first order in surface roughness height.
• Derivation of explicit formulas for radiated power.

Main Results:

• The scattered fields were determined based on the first-order approximation of surface roughness height.
• Explicit formulas quantify the power radiated by TE guided waves into the superstrate.
• The formulas directly relate radiated power to the surface autocorrelation function.

Conclusions:

• The developed theory provides a method to quantify scattering losses due to surface roughness in optical waveguides.
• The derived formulas are useful for practical applications in optical device design and performance prediction.