Integrated optics Mach-Zehnder interferometer sensor
Abstract (summary)
The first objective of this project was to design, fabricate and characterize straight channel optical waveguides prepared by plasma enhanced chemical vapor deposition (PECVD) of silicon oxynitride and by potassium ion exchange (PIE) in BK7 glass. This involved initial fabrication of slab waveguides by the two methods, and determination of the refractive index and thickness (or depth) of the deposited or diffused films. Having obtained these data, the next step was to design single-mode waveguides, which were then fabricated and characterized.
The main objective was to design, fabricate and characterize a nonsymmetric Mach-Zehnder interferometer sensor. This device is a refractive index sensor that is sensitive to the variations in the refractive index of the cladding layer. These variations can be created by an external perturbation such as change of temperature, pressure or chemical composition of the cladding layer. The design and a parametric study of the interferometer was performed using the finite difference beam propagation method (FD-BPM). The sensor testing and characterization was carried out using a solution of different concentrations of sugar in water as a model analyte material. During the measurements, the sensor was covered by a drop of the solution and the output was recorded. Finally, the sensitivities of the symmetric and non-symmetric Mach-Zehnder interferometers were evaluated and compared.