Research On Improving The Fractional Delay Of Slow Light In An Erbium-doped Fiber

In recent years, with the rapid development of optical fiber communication,communication bandwidth demand is growing. In order to solve thelight-electricity-light bottleneck in the conversion, all-optical communication startingto get people’s attention, and has good prospects for development. The optical bufferis the key to all-optical networks. So slow down the speed of light (slow light)technology has aroused intense interest in the study, and become popular in thecommunication science and technology research at the same time. Today, slow lighthas been a lot of methods and technical means, such as electromagnetically inducedtransparency (Electromagnetically Induced Transparency, EIT), coherent populationoscillation (Coherent Population Oscillation CPO) by stimulated Brillouin scattering(Stimulated Brillouin Scattering, SBS) Stimulated Raman Scattering (StimulatedRaman Scattering, SRS), optical parametric amplification (Optical ParametricAmplification OPA). This paper describes the use of coherent population oscillationeffect of the erbium-doped fiber slow light transmission, further discussion on how toimprove the relative delay of slow light. This parameter is characterized by the abilityof the media for information storage. The article consists of the following four parts:Introduction: the significance of the slow light research at home and abroad slow lightresearch progress and by comparative analysis of the advantages and disadvantages ofvarious slow light methods and techniques,which coherent population oscillationeffect in erbium-doped fiber to achieve the speed of light slows down moreadvantages. Coherent Population Oscillation effect has a lot of advantages, therequired experimental conditions is relatively low, the experimental phenomenon isobvious, carried out at room temperature. And the signal light work in the1550nmband, which gives the practical application of communications has brought greaterprospects.Chapter I: The main concept of the phase and group velocity of light from thestart, K-K dispersion relation of the to control lightwave transmission speed of the basic theory. When the refractive index with the dramatic changes in opticalfrequency, the group velocity of the light pulse will change. Which produce slow lightprogram (such as spectral hole burning technology, electromagnetically inducedtransparency (EIT), a double-wave coupling technology by stimulated Brillouinscattering (SBS) and stimulated Raman scattering (SRS), and so on) are the use ofstrong dispersion caused by a variety of means to influence the induced refractiveindex of the medium, and thus achieve the purpose of control of the speed of light.Chapter II: a brief overview of the technical rationale coherent population particleoscillation (CPO), the density matrix equations of motion of the two-level atomicsystem, the two-level atom system of monochromatic light field steady-state response,the optical Bloch equation, the pump field and probe field exist under the two-levelatomic system density matrix equation, the probe light absorption and refractive indexto be discussed.Chapter3: In the erbium-doped fiber to establish a theoretical model of thespeed of light slows down transmission, while taking advantage of this theoreticalmodel was simulated. First analysis of changes in the number of particles in themetastability, to discuss how to use coherent population oscillation effect to achievethe speed of light slows down transmission. Secondly, considering the relative delayCharacterization of the storage capacity of the media signal, to carry out an in-depthstudy on how to improve the erbium-doped fiber slows down the speed of lighttransmission relative delay, and thereby draw, select the high concentration of fiber toincrease the length of the fiber, close the pump light power, select the appropriatesignal light power can be effectively so that the relative delay or time delay increases.In the finality, the problems requiring further studies are discussed.