Heidar Keshavarz

Microwave photonics as an interdisciplinary branch is able to solve the fundamental challenges of microwave devices. One of the most important challenges is the bandwidth limitation of these devices. One of the common and widely used tools in microwaves is mixers. The common use of mixers is to change the frequency of a signal, but they can also have other functions. In this thesis, the analysis and review of one of the widely used photonic microwave mixers is discussed. This mixer consists of two Mach-Zehnder modulators with cascaded connections. In practice, electro-optical modulators can exhibit nonlinear behavior to a greater or lesser degree depending on their platform. A mathematical model that shows the nonlinear behavior and at the same time the operation of mixing signals in this mixer is presented. Having the analytical model in the closed form of the mathematical relationship enabled us to predict the outputs of this mixer. By adjusting the parameters of the mixer, including the bias voltage of the Mach-Zehnder modulators, different configurations are suggested for this mixer. Among these functions, we can mention the combined mixer with the ability to change the phase. It is also attempted to make the behavior of this phase shifting mixer as close as possible to an ideal phase shifter.