The Research Of Arbitrary Signal Generation Based On Spectral-hole Burning Crystal

With the development of arbitrary waveform generation(AWG)technology based on photon echoes gradually mature,it is necessary to study the photon echo theory more deeply.The model of photon echo makes researches have more ways and parameters to control the photon echo much more accuracy.Thus,it can improve the AWG technology.In this paper,the photon echo is generated by spectral hole-burning crystal.This paper will first introduce the spectral hole-burning crystal and photon echo phenomenon,and the study of the model of photon echo,while analyzing the advantages and disadvantages of each model;Then the Finite-Difference Time-Domain is introduced to deal with the problem of Maxwell-Bloch equations.The main content of this paper is followed as:1.The detailed deduction of optical Bloch equations.The expression of transmitted fields of optical nutation and optical free induction decay can be described by using optical Bloch equations.Then the optical Bloch equations of optical nutation and optical free induction decay are used to achieve the expression of the photon echo,and the variation of Bloch vectors in 3D Bloch Sphere during the production of two-pulse photon echo is plotted.2.The model of three-pulse photon echo based on optical Bloch equations.The three-pulse photon echo can be regarded as the phenomenon that have three optical nutation processes and three optical free induction decay processes,while its polarization of dipole moment is the maximum.The optical Bloch equations is used to deduce the expression of three-pulse photon echo,and the variation of Bloch vectors in 3D Bloch Sphere is plotted.We analyze the time delay of input pulses which have impact on the intensity of photon echo and analyze the optical depth which influence the efficiency of photon echo.The compressed echo can be regareded as the aggregation of numerous tiny 3PEs which generated by the ions of different frequencies at the same time.At last,the methods of improving the intensity and efficiency of compressed echo are discussed.3.We introduce the origin source of Finite-Difference Time-Domain and the Iterative Predictor Corrector Finite-Difference Time-Domain.The IPC-FDTD method is used to analyze the whole optical coherent transient process of two-and three-pulse photon echo.The variation of every vector is achieved and plotted in 3D Bloch Sphere based on simulation results.The transmitted field of optical coherent transient is plotted.The photon echo can be regarded as the rephasing process of atoms dipole moment.The amplitude of photon echo has e-exponential attenuation with the increase of input pulses' time delay.4.Based on photon echo theory,the theoretical analysis of the compressed pulse interval control is presented,and a high bit rate dual amplitude pulse position modulation signal generation method is proposed.A spectral grating can be formed in the inhomogeneous broadened absorption profile when two temporally overlapping linear frequency chirps are overlapped within a REIC.The DAPPM signal can be generated by the probe lasers interaction with the spectral grating.The location of echo can be controlled by adjusting the start time of probe lasers.In this method,the bit rate of the dual amplitude pulse position modulation signal can achieve 20Gbit/s.Compared with conventional methods,the bit rate of DAPPM improve an order of magnitude.