| In recent years,the demand of optical networks for people are becoming greater.A variety of multiplexing and demultiplexing techniques are used to multiplex and demultiplex signals,so that streams of information can transmit on the same carrier to achieve higher transmission capacity.At present,over 80% of the data on the internet are carried by optical networks,and the security issue in the process of information transmission has attracted more and more attention.One obvious advantage of optical chaotic communication is that it is easier to generate robustness and the power of chaotic signals produced are higher compared with traditional electronic chaotic communication.Furthermore,it is rather difficult for eavesdropper to recognize chaotic signal because the eavesdropper cannot yield the same synchronous chaotic signal with the transmitter.Integrated optics has received extensive attention due to the processing technology of optical components is extremely difficult and the components are relatively independent resulting in that the cost of components production,development and maintenance is rather high.The production of silicon-based integrated optical waveguide is quite mature now.It has compatibility with advanced microelectronics processing technology and is an important opportunity for the development of optoelectronic integrated industry.Currently mature integrated circuit manufacturing process has been able to reach 7 nm and 10 nm.Due to its low manufacturing cost and high electro-optical integration,silicon-based photonics devices have become the most promising materials for large-scale optoelectronic integration.This thesis focuses on the two-photon absorption(TPA)effect on the dynamic behaviors of the micro-ring resonator,as well as the dynamic behaviors of the cascaded microrings,the main work and the main findings are as follows:This dissertation first introduces the concept and research progress of chaotic secure communication.The composition and working principle of the coupler,the all-pass microring resonator and add/drop microring resonator are briefly introduced.The coupled-mode equations and matrix equations of the linear symmetric coupler are also analyzed.In addition,the non-linear Lugiato-Lefever Equation model and its brief derivation process are introduced.The two-photon absorption process and its impact are analyzed and introduced.The modulation instability in the microring resonator is analyzed by introducing the perturbation terminto the steady-state solution.Secondly,according to the Ikeda delay equation,the expression of the coupling relation between the all-pass microring and add/drop microring are deduced.The effects of two-photon absorption on the dynamic behaviors of all-pass microring resonator and add/drop microring resonator were studied by iterative method,normalized method and linear stability method.The influence of two-photon absorption coefficient on the steady state,multi-period,bistable and chaotic regions of the two kinds of microring resonators is analyzed.Due to the influence of TPA on the dynamic behaviors microring resonators,such that this study has a certain significance for chaotic communication systems,optical switches and integrated optical design.At last,the dissertation studies the dynamic behaviors of the cascaded microring resonator by iterative method.Results show that there are bifurcation,bistable and chaotic states in the cascaded microring resonator.This dissertation also studies the influence of the through coupling coefficient on the dynamics and finds that the dynamics is related to the transmission coupling coefficient.When the transmission coupling coefficient is small,the transmitted optical signal of the microring resonator's ‘Through' port and ‘Drop' port may be stable;and if the coupling coefficient is large,the outputs are more likely to exhibit non-linear dynamics,such as doubling period bifurcation and chaos,and the device can be used to generate chaotic signals for secure communications. |
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