Research On Coupling Theory And Application Of Optoelectronic Oscillators

Due to the significant advantages of photonic technology,such as high frequency and large bandwidth,the technology of generating microwave signals based on microwave photonics has attracted substantial attention inrecent years.Optoelectronics oscillator(OEO)is a microwave photonics signal generation device to convert optical signals to microwave signals through the optoelectronic feedback loop.OEOs are widely used to generate ultra-low phase noise single-frequency microwave signals and other different kinds of microwave signals.OEO has been a core structure in modern communication,sensing,signal processing,and other fields.In addition,the rapid development of electronic-photonic convergence technology has taken microwave photonics to a new level,and the scalability and reliability of OEO have been greatly improved.The new technology can support more complex OEO structures.Coupled OEO networks have attracted widespread attention in the fields of chaotic communication,signal generation,and neural networks.In the past,the coupled OEO structures were generally implemented by multi-loop structures or multi-oscillator spatial structures.Compared with these studies,this thesis utilizes the concept of synthetic dimensionality in photonics to construct the coupling system of OEO by using system parameters instead of spatial dimensionality,such as frequency,polarization,wavelength,and multiple pulse trains.In this thesis,a coupled OEO system is constructed using frequency coupling and timing pulses,and numerical simulations and experimental verification are performed,which provides a new idea for the study of oscillator coupling.The main research contents and innovation points are as follows:This thesis investigates the dynamic balance of multiple longitudinal modes of OEO under frequency coupling.In the conventional OEO structure,the output of OEO is a single-frequency oscillation or multifrequency superposition of arbitrary waveforms through mode competition.We investigate the phenomenon of frequency mode coupling via a multiple passband filter,which manifests itself as spontaneous frequency hopping behavior in OEO.This thesis studies the phenomenon of frequency hopping signals observed by chance in OEO.For this phenomenon of the spontaneous frequency hopping behavior in OEO,theoretical modeling and simulation analysis are performed.The phenomenon turns out to be universal.The spontaneous frequency hopping behavior is the result of the dynamic equilibrium of mutual coupling between multiple longitudinal modes in OEO.We use microwave photonic filters to construct dualpassband filters to study the coupling of frequency longitudinal modes in OEO.Based on the characteristics of spontaneous frequency hopping,we construct a new type of frequency hopping OEO with the advantages of high hopping speed and low phase noise,which generates a phase noise of-133.1 dBc/Hz@10 kHz.It can provide a new design idea for frequency hopping generation based on microwave photonics.In addition,time freedom degrees are also used to construct OEO coupled OEO networks.In this thesis,a novel experimental scheme based on time-division multiplexing of pulsed OEO to achieve PT symmetry is proposed.Each microwave pulse can be regarded as an independent OEO,and the gain/loss ratio and the coupling coefficients are controlled independently.The microwave pulses are coupled at the optical link;thus PT-symmetry occurs between the coupling microwave pulses.Compared with the past PT-symmetric OEO,the pulsed OEO uses multiple pulses to realize mutual coupling in a single OEO cavity,which effectively observes the PT-symmetry from symmetry state to broken state and demonstrates the phase transition behavior of spontaneous symmetry breaking of PTsymmetry.With the idea of synthetic dimension,we use the temporal dimension instead of the spatial dimension.The coupling technique of pulsed OEO can be applied to the study of physical phenomena such as higher-order PT symmetry and non-Hermitian systems.Also,this paper provides some discussion on the effect of phase perturbation on the imaginary coupling coefficients.Meanwhile,this thesis first proposes a new type of coherent Ising machine(CIM)based on an optical parametric oscillator(OEPO),called the microwave photonic Ising machine.We use ultrashort microwave pulses in OEPO as the spin carriers of the Ising model to achieve an Ising machine with high stability at room temperature.We implemented the Ising machine with 25,600 spins and performed experimental simulations of one-and two-dimensional Ising models.Compared with the past CIM,the microwave photonic Ising machine has higher coherence and excellent nonlinear transfer function,and its solution success rate is higher.In addition,the high coherence ensures its stable operation for 12 hours.Taking advantage of the high scalability and compatibility of high-speed electronic devices,the microwave photon Ising machine can be effectively extended to the solution of combinatorial optimization problems.The microwave photonic Ising machine provides a new physical implementation for the research of CIM,extends the research direction of optical computing,and provides new possibilities for the solution of combinatorial optimization problems.