Experiments on light waves in a thin tapered film and a new light-wave coupler

Abstract

We discuss experiments in an asymmetric optical waveguide which is simply a dielectric film deposited on a substrate. The film has a tapered edge. Near this edge and depending on the angle of incidence, a guided light wave in the film may be totally reflected or it can enter into the substrate as radiation modes. In the latter case, the tapered film edge is used here to couple light energy into or out of the film. © 1971 The American Institute of Physics.