Study On Nonlinear Clustering Behaviors Based On Silicon Optical Modulator

With the rapidly developed telecommunication technology and computer science nowadays, the demand for information and the capacity of processing are all explosively increased. Compared to the traditional electronic communication, which shows parasitic effects and bandwidth limits under high frequency communication, optical communication has become the ideal solution to replace the metal interconnection due to its advantages of more robustness and wider bandwidth. The vast bandwidth, high extinction ratio, low power consumption and low cost, all these advantages lead the silicon optical modulator to a wide application for prospective optical communication devices. Electro-optic delay feedback system based on silicon optical modulator has been a popular research topic, so is the system's dynamical behaviors, due to the silicon optical modulator's nonlinear features and its inevitable time delay, noise interference problems in communication systems.This article studied the electro-optic delay feedback system based on silicon Mach-Zehnder modulator. Periodic and chaotic states were observed in our experiments, and chimera state was found in silicon optical modulator system for the first time. A theoretical model was built to analyze the experiment system, and the simulative results by numerical simulated are consistent to the experiment ones, which will help us to deeply understand the nonlinear features of silicon optical modulator and the internal mechanism of collective behaviors, such as chimera state and so on.The article is constructed as follows:The first chapter is introduction, the background and significance of our research are introduced. Basic knowledge and theories of nonlinear dynamics, including the nonlinear system's dynamical equations, solution forms and stability, bifurcation, nonlinear clustering behaviors and the principle of nonlinear clustering behaviors by using silicon Mach-Zehnder modulator. There are also brief introductions to the research history and status in the world, nonlinear signals like chaos and synchronization generated by circuit systems are usually with small bandwidth and high transmission loss, thus it is difficult to applied in high speed and long distance communication. Therefore, the wider bandwidth optical systems and electro-optic systems are more appealed to construct high speed and low transmission loss optical communication systems. Based on these facts above, silicon Mach-Zehnder modulator was designed to construct an simple electro-optic delay feedback system and the nonlinear clustering behaviors were studied through experiment and numerical simulation calculation.The second chapter introduces the typical electro-optic delay feedback system generating chaos signal, and analyzes a delay feedback system based on LiNbO3 Mach-Zehnder modulator and another with Fabry-Perot interferometer through numerical simulations.The third chapter describes the whole experimental system,explanation on how it works, and observation on electric signal by adjusting the laser wavelength and optical amplifier gain. Periodic,chimera and chaos state are obtained in our experiments.The forth chapter shows the theoretical model of our experimental system and based on this model we analyze the system nonlinearity and derive the system equations. Numerical simulations are calculated to study the influences to output signal with parameters varying. The results we obtained are quite well consistent to the experimental ones.Besides, we compared the differences among the systems based on silicon Mach-Zehnder modulator, LiNbO3 Mach-Zehnder modulator and Fabry-Perot interferometer.The last chapter summarize the work in this article. Some follow-up works planned to be done and prospects of the study are presented as well.