INTRODUCTION This design proposal is about the study of an optical device known as the Mach-Zehnder interferometer (MZI) via simulation and to verify its operation experimentally. The device will be fabricated using Silicon over Insulator (SOI) technology. These types of interferometers are commonly employed in telecommunications applications such as switches, modulators and filters. Also, in sensing applications, MZI’s are commonly employed to allow one of the arms of a interferometer to interact with an analyte via a waveguide’s evanescent field. In this draft design, two devices were chosen. The first is a simple MZI with different path length differences ΔL. An explanation of a MZI operation is thus presented. The second device is a basic filter based on two cascaded interferometers. Also, the basic theory of a lossless two stage MZI filter is presented. Here in this report simulations in terms of optical component and circuit device are shown, which later on will be compared with experimental results after device fabrication.