Theoretical Study Of Kerr Frequency Comb Based On High-Q Microresonator

Since optical frequency comb technique has brought a huge prospect in optical frequency measurement and communications applications, the research on micro-ring resonators Kerr comb has become a hot point recently, with its great advantages of a wide spectrum, low power consumption, high stability, small size and easy integration. The experiment has confirmed the Kerr optical micro-ring resonator can produce a wide spectrum of stable frequency comb, however it is still lack of theoretical study, such as there is no clear and exactly definition on its formation process, which hinders the further realization of its application. Based on the high-Q micro-ring resonators this thesis focuses on Kerr comb mechanisms, principles, characteristics, and related applications. The main content of the work and innovation are as follows.Firstly, LLE equation has been used to establish Kerr comb generation model, taking into consideration of many possible physical effects such as micro ring loss, detuning, dispersion, etc. Through this simulation models the article shows four different stages of the Kerr optical frequency comb formation process in MATLAB software, and the main mechanism for each stage has been analyzed, including the four-wave mixing and modulation instability. The simulation results indicate that the process has a close relation to its pump power, and detuning, which agrees well with corresponding experimental results.Secondly, the characteristics of the Kerr optical comb have been analyzed. Within the understanding that the noise seed influencing greatly on Kerr comb generation, the article explores the influence of random noise seed in further more details. The cases include injecting the random seed at the be ginning, as well as at other different stages in the optical comb generation process. The results show that, the coherence between different modes or wavelength generally is low, which is resulted from the varieties of complex nonlinear effects in the Kerr comb generation process.Thirdly, due to the great advantages of Kerr comb, such as wide spectrum, narrow line width, high stability, further research on its application in optical communication system has been explored. At first its use as amplitude modulation source has been studied in the article, measuring the receiving characteristics including eye diagrams and the maximum Q value of the non-coherent modulation communication system. It theoretically proves its good performance as modulation source. Secondly, analysis of the receiving characteristics in optical OFDM transmission system has been made by introducing the Kerr comb as coherent modulated light source. The results also s how that the Kerr comb performance well in coherent modulation communication system.