Research On The Adiabatic Conversion Mechanism And Devices Using Silicon-based Micro-cavity

In modern society,the integration of microelectronic devices is getting higher,and the demand for the rate and bandwidth of data transmission is higher.The traditional electronic devices have reached the transmission limit.Because the silicon-based optoelectronic devices' low cost,high transmission bandwidth,fast transmission rate,anti-electromagnetic interference,compatibility with CMOS and so on,are widely used in many important fields.They will become an important cornerstone of the next generation of information technology.The silicon-based coupled micro-ring resonator is an important silicon-based optoelectronic base device with simple structure and excellent performance.In recent years,adiabatic wavelength conversion using silicon-based microring resonators is a hotspot,which shifts the photon frequency limited to the cavity to a new frequency by dynamically changing certain properties of the microcavity within a time less than the lifetime of the photon.It can be used for wavelength division multiplexing.One research is to use the EIT-like effect of a silicon-based coupled microring resonator,which makes the group speed of the light is suddenly reduced to realize slow light.This can be used for delay,buffering and storage of light.This method breaks the balance between time delay and bandwidth in the photonic structure,and can greatly extend the storage time.It's a good way to achieve optical storage.In this paper,the adiabatic conversion mechanism and device of silicon-based microcavity are studied in depth,and the adiabatic wavelength conversion in the single-ring resonator and the class-like traveling wave F-P resonator is studied.An optical storage structure based on dual-waveguide coupled double rings(2R2B)is proposed.By controlling the adiabatic of the micro-ring,the Q value of the system can be quickly changed to realize the storage and release of light.The main contents are as follows:(1)The adiabatic wavelength conversion process in the single-ring resonator and the class-like traveling wave F-P resonator is simulated and analyzed by FDTD.It is verified that the adiabatic wavelength conversion of the micro-cavity is independent of the refractive index change rate,and the wavelength conversion amount is proportional to the refractive index change,and the factors that influence the wavelength conversion efficiency.This wavelength conversion is mainly performed by changing the refractive index of the microring,and the change of the refractive index requires spatial uniformity,and the non-uniform change causes non-adiabatic wavelength conversion in the ring to generate multiple wavelengths.(2)Based on the transfer matrix method and the temporal coupled mode theory,the theoretical models of the single-ring resonator and 2R2 B structure are established.Then we calculated the relationship of the output and the resonant wavelength,amplitude transmittance and the ratio of double-ring radius in the single-ring and 2R2 B structures by Matlab.We confirm the parameters of double rings and the wavelength which can cause double loop resonance at the initial state,and the dynamic change of the time domain light field of the structure is calculated.Then,the 2R2 B structure is numerically simulated by FDTD,and the class-like electromagnetic-induced transparent resonant peak spectrum is obtained in the weak coupling.It is theoretically confirmed that the Q value of coupled micro-ring system can be effectively controlled by the fast adjustment of the refractive index of the waveguide-coupled micro-ring,and achieve dynamic storage and release of the optical signal.(3)By conducting many technologies such as Electron-beam lithography and Inductively coupled plasma etching,we fabricate the silicon-based single-ring resonator and the class-like traveling wave F-P resonator.The frequency domain spectra of the two devices are tested.The transmission characteristics are consistent with theoretical simulations and the Q value exceeds 7000.At the same time,the 2R2 B structure device which based on coupling of low Q ring(radius ~28?m)and high Q ring(radius ~21?m)is prepared.The coupling spacing between the double rings was adjusted to obtain an ideal class-like electromagnetic-induced transparent resonant peak.After adjusting the resonance peak of a micro-cavity,the Q value of the coupled system changes significantly(from 10204 to 19132),so the dynamic storage and release of the optical signal can be achieved through adiabatic regulation.