Applied physics

, Volume 1, Issue 1, pp 55–68

Planar leaky light-guides and couplers

  • R. Ulrich
  • W. Prettl
Contributed Papers

DOI: 10.1007/BF00886805

Cite this article as:
Ulrich, R. & Prettl, W. Appl. Phys. (1973) 1: 55. doi:10.1007/BF00886805


A quantitative theory of light propagation in a dielectric slab guide with general cladding media is presented. It is based on a plane wave which bounces in a zigzag fashion along the guide as a result of total or partial reflections at the two surfaces of the film. Two mechanisms are considered which contribute to the attenuation of the guide: losses due to absorption in the slab and cladding materials, and radiation losses if the guide is a leaky one. We point out the significance of the Goos-Hänchen effect for all questions relating to the power flow in the slab guide. The theory is illustrated by discussing dispersion and attenuation of guides with various low-index and high-index claddings, operating above and below cutoff. The low-index leaky guide is considered particularly in detail. Its high attenuation by leakage can be reduced to practically acceptable values (<1d B/cm) by increasing the film thickness to ≳ 40λ. One application of this guide is in the leaky wave coupler. This coupler may be viewed as a prism-film coupler simplified by omission of the gap. It offers a new approach to the problem of broad-band coupling to thin-film light guides.

Index Headings

Integrated opticsThin filmsGoos-Hänchen effect

Copyright information

© Springer-Verlag 1973

Authors and Affiliations

  • R. Ulrich
    • 1
  • W. Prettl
    • 1
  1. 1.Max-Planck-Institut für FestkörperforschungStuttgartF.R. Germany