Ridge waveguide without high refractive index layer: multilayer side cladded ridge waveguide

Light propagation in a waveguide without a high refractive index layer as a guiding region is described. The waveguide consists of a ridge fabricated from a fused quartz substrate, a low refractive index clad layer of Au, and a high refractive index clad layer of a solution of glycerin in water or of air. From the near field patterns, the light confinement was confirmed. The coupling angles in the experiments were consistent with the calculated values using the equivalent refractive index method.