On the basis of the transfer-matrix technique, the concept of the equivalent attenuated vector is proposed andused to analyze the characteristics of the propagating modes in planar optical waveguides with gradedrefractive-index profile; an exact analytic equation is obtained for the dispersion equation of arbitrary gradedrefractive-index planar optical waveguides.

We report on a coupling method, which transfers energy of a light beam from free space into asymmetrical metal-cladding optical waveguide from the top surface without employing the prism,grating, tapered film, and other coupling components. In the experiment, a glass flat with a thicknessabout 100um, sandwiched between two gold films is used as a guiding layer. A top gold film of 46nm thick serves as a coupling layer as well as the cladding and a base gold film of 200nm servesas the substrate of the waveguide. Up to 50% of the incident light energy fed into the waveguide hasbeen demonstrated.

We present a novel matrix approach to proving that the phase shift at a turning point in a planar optical waveguideis exactly equal to π rather than to π/2 or to some other value. We also show the existence of phasecontributions from reflected subwaves, which to our knowledge have never been taken into account previously.

An oscillating wave sensor based on Fabry-Perot resonance modes has been developed. Different fromthe surface plasmon resonance sensors and the waveguide mode sensors in which the sample is locatedin the evanescent field region, the proposed device contains the sample in the core region that supportsthe oscillating field. Owing to the strong concentration of the electromagnetic field in the sensingmedium, the proposed device exhibits unusual sensitivity enhancement, which has never been exploitedin any other devices.

A simple displacement measurement based on the attenuated total reflection technique is proposedand experimentally demonstrated. By analyzing the fringe shift of the reflective pattern recorded on a CCD camera, a slight displacement, which corresponds to a change in the waveguide thickness, can be determined in real time with adequate accuracy. The measurement range of this method isabout 240um, and its accuracy can reach 0.05um.