Study On The Controlled Light Speed In Single-stage Erbium-doped Fiber Pumped By Dual-frequency Laser At Room Temperature

In recent years,high capacity and high speed optical fiber stabilization systems are needed for photonic communication.To solve the problem of optical path blockage,optical routing and optical buffer are needed to solve the problem.The slow light generated by the coherent population oscillation(CPO)principle has many advantages.For example,the device is easy to operate,can be operated at room temperature,and the slow light phenomenon is obvious.We get rare-earth doped fibers by injecting dopants into them,which have good optical properties,such as strong nonlinearity,flexible dispersion,On the basis of this characteristic,the coherent population oscillation technique is used to realize the slow propagation of light group and the slowing of light in rare-earth ion doped fiber at the same time.This study is of practical significance.The single-stage erbium-doped fiber is used as the medium of slow light,and the single-stage erbium-doped fiber is pumped by 980 nm and 1480 nm dual-frequency laser to produce slow light.The theoretical model of this transmission system is obtained and simulated.The advantages of dual-frequency laser pumped single-stage erbium-doped fiber are summarized and compared.This paper broadens the way to change the speed of light transmission and provides the theoretical basis for future experiments.Main content:The first chapter :the research background and significance of the speed of light,the current situation and research content of the speed of light at home and abroad are described in detail.The second chapter: the theory of phase velocity and group velocity,K-K dispersion and coherent population oscillation(CPO)technique are explained.The third chapter: using 980 nm and 1480 nm dual-frequency laser pumped single-stage erbium-doped fiber to produce slow light,a theoretical model of controlled light speed is established.The energy level transition rate equation oferbium ion is taken as the basis,according to the propagation equation of co-propagation and counter-propagation dual-frequency laser pumping.The relation of ground state particle number,time advancement,fractional advancement and relative modulation attenuation with two pump power is obtained.The four chapter: on the basis of the third chapter,the phenomenon of ultra-slow light is generated at different pumping light power ratio M when the dual-frequency laser pump is injected in the co-propagation and counter-propagation,and the time delay or time advancement,fractional delay or fractional advancement is discussed,and the relative modulation attenuation changes with the modulation frequency;It also discusses the change of the optimal modulation frequency and the maximum relative time delay with the power ratio of the pump under the pump ratio of a certain number,finally the M is changed,and the two pump light power values are changed at the same time,so that the time delay,fractional delay and the variation relation of the modulation frequency are obtained.