Modes Tuning Mechanism In Optical Ring Resonators

As an important component in the field of optoelectronics,optical ring resonators are also regarded as an indispensable part of the development of optoelectronic chips.With the flexible and compact structure,natural wavelength selectivity,local light field enhancement effect,and perfect platform compatibility,the optical ring resonators are of great theoretical and applied research value,which has been widely used in the fields of optical nonlinearity,optical sensing,optical communication,fast and slow light,and quantum optics.The output response of traditional ring resonators has been unable to meet the variety of needs in modern application scenarios.Therefore,in recent years,researchers have proposed a variety of new ring resonators,which realize a series of practical applications such as wavelength division multiplexing,optical delay,optical buffer,quantum information transmission,and optical computing by tuning the light field mode.However,the research of optical ring resonators mainly focuses on the nonfeedback structure now,with little attention on the feedback ring resonator.Moreover,the system is not concise enough for multiple resonant modes circumstances,and the mode tuning methods need to be further studied.On viewing the above problems,this paper intends to explore the physical mechanism of resonant modes in different ring resonator structures and study the tuning methods of resonant modes,which helps to simplify the overall structure and improve the performance of ring resonators.In this dissertation,based on the typical physical phenomena in ring resonators such as Fano,Electromagnetically induced transparency(EIT),and Autler-Towns splitting(ATS)phenomena,the new feedback ring resonance structures were proposed,and the physical mechanism of mode tuning was studied and verified in the experiment.The detailed work is as follows:Using the transfer matrix method and temporal coupled-mode theory,the characteristics of add-drop filter of double waveguide coupled single ring were studied respectively,and the transmission responses of ring resonator under three coupling states were analyzed.The basic characteristics of two kinds of feedback ring resonators were studied,focusing on the role of loss and phase of feedback waveguide in mode regulations,and the application scenarios of different resonator structures were given.Aiming at the problem of mode independent tuning in multiple resonant modes circumstance,an asymmetric feedback ring resonator structure was proposed,and the isolation method between tuning region and non-tuning region was studied.With the design of asymmetric feedback structure,the transmission equations of two feedback ring resonators can be separated from each other,thus the modes from two different resonators can be tuned independently.The characteristics of transmission spectra were analyzed under the resonant mode independent tuning,and the method for realizing multiple transparent windows was explored theoretically.Finally,the output effect of three transparent windows in single resonance valley was realized,which can be used for optical storage and optical calculation.For the complex structure and excessive tuning devices to realize the double Fano phenomenon,a feedback ring resonator with two output ports was proposed,which realized the antisymmetric double Fano output effect that needs four ring resonators,eliminating additional phase and wavelength control devices.The two output responses were studied using the temporal coupled-mode theory.The optical field transmission process was analyzed in the overall structure,and the physical mechanism of Fano resonance and EIT resonance was explained theoretically.The asymmetric double Fano phenomenon was obtained in the two output ports experimentally,the result of the linear change of 23.7db extinction ratio in the 0.102 free spectral range was realized,and the method to enhance its performance was proposed.The results can be used for optical intensity sensing and laser wavelength monitoring.For the complex and unstable system to realize ATS,the method using a single-mode microfiber knot was studied.The physical characteristics of the multi-mode microfiber knot in the transition region were explored,and the physical model of overall optical field propagation was established.The transmission response of the multi-mode microfiber knot was studied in the experiment,and the effect of two transparent windows in the single resonant Valley was realized by adjusting the microring parameters with an optical fiber probe.The research showed that the ATS phenomenon originated from two mode splitting of the same order but different polarization states.In this paper,the effect of mode independent tuning under multiple resonant modes circumstances was realized,and the problem of crosstalk between tuning area and nontuning area was solved.The antisymmetric double Fano structure is optimized to avoid additional tuning devices.ATS phenomenon was observed in the microfiber knot for the first time.Compared with other systems to observe this phenomenon,the simple and stable structure was easy to be integrated with other systems.The above research provides a reference for the further development of ring resonators in the fields of optical communication,optical sensing,semiconductor laser wavelength monitoring,and fast and slow light.