Research On A Novel Reconfigurable Optical Directed Logic Device Based On Microring Resonators

In order to solve the contradiction between people's urgent demand for high-speed and large capacity information processing and the bottlenecks encountered in the development of traditional integrated circuits,more and more researchers at home and abroad focus on the optical information processing technology which uses optics instead of electronics as the information carrier.The optical directed logic device based on silicon-based microring resonators is one of the important parts of on-chip optical information processing technology.It synthesizes the characteristics of the easy controllability of electron and the fast transmission speed of photon,and has a series of advantages such as low signal delay,large bandwidth,easy to control,large-scale integration with electronic components and so on.Therefore,it is considered to be one of the effective solutions to the current"electronic bottleneck"of Moore's Law.At present,most of the optical directed logic devices reported at home and abroad can only realize one or several logic operations,and a few devices that can realize any logic operations by multi-wavelength are based on wavelength division multiplexing technology,which have great limitations on the practicality and manufacturing cost of the devices.In this dissertation,a novel reconfigurable optical directed logic device based on microring resonators is studied.For the first time,it is proposed to ultilize optical mode division multiplexing technology,combined with tunable micrcring resonators to realize the reconfigurable optical directed logic operation.Not only can arbitrary logic functions be realized according to the actual demands,but also can avoid the multi-wavelength problem brought by wavelength division multiplexing.So that the proposed device has good reconfigurable and expandable ability,and its flexibility and practicality is fully enhanced.The core components of the proposed device are microring resonators and mode multiplexer/demultiplexer.Therefore,the theory of optical waveguide and microring resonator are introduced firstly in this dissertation.In perspective of the theory of optical waveguide,the mode transmission characteristics of the light inside the waveguide is discussed,and the minimum fully coupled length is solved by using the coupled mode theory and phase matching conditions.In the aspect of microring resonators,the common models such as scattering matrix theory and time coupled mode theory are mainly discussed.The common modulation methods are introduced,and the optical mode splitting characteristics of microring are further analyzed.For the first time,a microring resonator with feedback coupled waveguide is proposed and experimentaly demonstrated to generate the optical mode splitting.The experimental results show that the extinction ratio of the resonant peak is more than 21 dB,and the splitting wavelength is of 0.37 nm,which provides another important method for the study of the mode splitting characteristics in the field of optical information processing in the future.Finally,the principle of the novel reconfigurable optical directed logic device based on microring resonators is demonstrated.Through the theoretical modeling and simulation of the proposed device,the key parameters such as the coupling length of the mode multiplexer/demultiplexer,and the coupling gap between the microring and the straight waveguide are determined.The experimental results show that the extinction ratio of the through port of a single microring can reach 24.5 dB under the selected parameters.For mode multiplexer/demultiplexer,the transmission loss of TE₁mode is about-2.5 dB in the entire C-band,and the crosstalk with TE₀ mode and TE₂mode is less than-15.5 dB.For TE₂ mode,the transmission loss is about-2.8 dB,and the crosstalk with TE₁ mode and TE₀ mode is less than-24.8 dB.As a proof of principle,the static spectra and dynamic responses of the device are characterized by the thermos-optic modulation scheme.In the dynamic test,the logical operands are non-return to zero binary pseudo-random electric signals with a rate of 10 Kbps.The experimental results show that the proposed device can correctly complete"AND","OR","NOT"and their combined logical operations.Thus,it can well realize any logical operations according to actual demands.The proposed device is expected to play an important role in large-scale optoelectronic hybrid integrated circuits in the future,which provides an important reference for the research and development of new information processing technology that breaks through the von Neumann computing structure.