Loss calculations in weakly-guiding optical dielectric waveguides

• Main Author: Adams, M.J (Author)
• Format: Article
• Language: English
• Published: 1977.
• Subjects: Article
• Online Access: Get fulltext

 The application of perturbation theory to a three-layer weakly-guiding slab waveguide composed of lossy dielectric media yields a simple formula for the attenuation coefficient alpha of a guided mode: α = (Σ³_i=1 α_i P_i) / (Σ³_i=1 P_i), where α_i, P_i are respectively the loss coefficient and model power in region i (i = 1,2,3). It is shown that this result can also be obtained from arguments based purely on geometric optics. The result is easily extended to apply to circularly-symmetric optical fibres where it yields confirmation of an earlier approximation for the power ratios P_i/Σ²_i=1P_i.