Theoretical analysis of TM nonlinear asymmetrical waveguide optical sensors

An extensive analytical analysis is carried out to investigate TM nonlinear asymmetrical waveguide sensors. The structure consists of a thin film embedded between two nonlinear media. The effect of the nonlinearity of the cladding and the substrate on the sensitivity of the sensor is studied. A comparison between the proposed nonlinear sensor and the conventional linear sensor is presented to show that nonlinear sensors have higher sensitivities. The condition required to maximize the sensitivity is also derived to provide the designer with the optimum structure of the proposed nonlinear sensor.