基于光子学的宽带信号获取研究
发布时间：2019-06-02 15:48
【摘要】：宽带信号的获取成了现代雷达,射电天文学,电子对抗以及另外一些先进的通信系统必不可少的技术。传统基于电器件的信号获取具有带宽小,功率损耗大以及易受电磁干扰等缺点。光子学技术由于具有带宽大、重量轻、损耗低以及抗电磁干扰等诸多优点,成为未来宽带信号获取的一个重要发展方向。目前,基于光子学宽带信号获取的两种重要技术是光子模数转换技术和光子压缩感知技术。本论文中,我们以提高信号获取的性能为目的,包括精度更高,带宽更大,提出多种基于光子模数转换和光子压缩感知的宽带信号获取方案。论文首先介绍了微波光子学的研究背景、主要应用方向和重要器件。然后针对光子学技术在宽带信号获取中的应用进行了研究,介绍了基于光子模数转换和光子压缩感知的宽带信号获取以及与相应的电技术相比存在的优势。针对现有技术存在的问题,提出了一些创新的结构和方案,通过仿真和实验对系统进行了验证。论文的主要创新点和学术贡献如下：1.通过分析光子模数转换经典模型(Taylor方案)存在的限制,提出了一种基于差分编码的光子模数转换方案,并通过数值仿真对系统进行了验证。方案中利用了一个相位调制器(PM)和一个干涉仪并结合波分复用技术实现了输入信号差分形式的编码,克服Taylor方案中调制器电极长度成倍增长的问题,从而提高了系统的可行性。另外,差分编码的实现提高了系统的等效量化等级。为了进一步提高系统的性能,我们利用双驱动的非平衡调制器代替PM和干涉仪,不仅可以减少系统的体积,降低系统的损耗,也有利用系统的集成。2.在深入研究对称数字系统(symmetrical number system, SNS)的编码特性以及SNS在模数转换中的应用的基础上,提出了改进的基于SNS的光子模数转换方案。方案中利用等半波电压的干涉仪以及多个电比较器,并通过设计干涉仪之间的相移,实现了具有格雷码性质的SNS编码,从而大大提高了系统的纠错能力。为了消除光源幅度抖动的影响,提出将平衡检测技术应用到系统中,从而提高了系统的稳定性。3.在充分理解压缩感知基本原理的基础上,用理论研究和数值仿真的方法详细分析了基于光子压缩感知的宽带信号获取。介绍了基于空间光调制器(SLM)和电光调制器(EOM)的光子压缩感知方案,通过实验验证了系统的可行性以及存在的问题。提出基于平衡马赫增德尔调制器(MZM)结构的随机调制方式,简化了压缩感知系统的数学模型,实现了零均值的随机观测矩阵,提高了系统的性能。4.针对压缩感知系统中,随机序列的速率需达到输入信号带宽两倍的限制,提出基于光时域拉伸技术的压缩感知方案。光时域拉伸技术充分利用色散导致的群延时对加载在啁啾光信号上的射频信号进行拉伸处理。将其与压缩感知技术相结合不仅可以降低输入信号的速率,从而降低系统对随机序列速率的要求,而且可以进一步降低系统的采样速率。为了消除光强度调制和直接检测引入的直流,进一步提出基于平衡结构的光时域拉伸子系统,提高了信号获取的信噪比。5.提出三种基于微波光子滤波的压缩感知方案,在光域中实现压缩感知中的低通滤波或累加过程。方案一利用多波长的非相干光源和色散介质,在群速度色散的作用下实现了随机调制信号相邻比特位之间的累加。方案二利用单波长的连续光源和色散介质,实现了随机调制信号的低通滤波,简化了系统。方案三利用集成芯片的技术实现了基于光频率梳妆的多抽头微波光子滤波器,增加了滤波响应的旁瓣抑制比,减少了信号恢复的误差,有利于系统向集成化的方向发展。通过实验和数值仿真验证了系统实现宽带稀疏信号获取的性能。
[Abstract]:The acquisition of broadband signals is an essential technology for modern radar, radio astronomy, electronic warfare, and other advanced communication systems. The traditional electric appliance-based signal acquisition has the disadvantages of small bandwidth, large power loss and susceptibility to electromagnetic interference, and the like. The photonics technology has the advantages of large bandwidth, light weight, low loss and anti-electromagnetic interference, and becomes an important development direction of the future broadband signal acquisition. At present, two important technologies based on photonic broadband signal acquisition are photonic analog-to-digital conversion technology and photon compression sensing technology. In this paper, we aim to improve the performance of signal acquisition, including higher precision and larger bandwidth, and propose a wide variety of wideband signal acquisition schemes based on photon analog-to-digital conversion and photon-compression sensing. The paper first introduces the research background, main application direction and important device of microwave photonics. The application of the photon-based analog-to-digital conversion and the photon-compression-sensing based broadband signal acquisition and its advantages over the corresponding electric technology are introduced. Aiming at the problems existing in the prior art, some innovative structures and schemes are put forward, and the system is verified by simulation and experiment. The main innovation points and academic contributions of the paper are as follows:1. By analyzing the limitation of the classical model of the photon analog-to-digital conversion (Taylor's scheme), a photonic analog-to-digital conversion scheme based on differential coding is proposed, and the system is validated by numerical simulation. In the scheme, a phase modulator (PM) and an interferometer are used, and the code of the input signal differential form is realized by combining the wavelength division multiplexing technology, so that the problem that the length of the modulator electrode in the Taylor scheme is doubled is overcome, and the feasibility of the system is improved. In addition, the implementation of differential coding improves the equivalent quantization level of the system. In order to further improve the performance of the system, we use the dual-drive, non-balanced modulator instead of the PM and the interferometer, not only to reduce the volume of the system, to reduce the loss of the system, but also to utilize the integration of the system. On the basis of in-depth study of the coding characteristics of the symphonic digital system (SNS) and the application of the SNS in the analog-to-digital conversion, an improved SNS-based photonic analog-to-digital conversion scheme is proposed. An interferometer with equal half-wave voltage and a plurality of electric comparators are used in the scheme, and the SNS coding with the Gray code property is realized by designing the phase shift between the interferometers, thereby greatly improving the error correction capability of the system. In order to eliminate the influence of the amplitude of the light source, it is proposed to apply the balance detection technique to the system, thus the stability of the system is improved. On the basis of fully understanding the basic principle of the compression perception, the method of theoretical research and numerical simulation is used to analyze the broadband signal acquisition based on the photon-compression perception. The photon compression sensing scheme based on spatial light modulator (SLM) and electro-optical modulator (EOM) is introduced, and the feasibility and problems of the system are verified by experiments. The random modulation method based on the structure of the balanced Mach-Zehnder modulator (MZM) is proposed, the mathematical model of the compression-sensing system is simplified, and the random observation matrix with zero mean value is realized, and the performance of the system is improved. In the compression-aware system, the rate of the random sequence needs to reach the limit of twice the bandwidth of the input signal, and a compression-sensing scheme based on the optical time-domain stretching technology is proposed. The optical time-domain stretching technology makes full use of the group delay caused by dispersion to stretch the radio-frequency signal loaded on the optical signal. The combination with the compression-sensing technology can not only reduce the rate of the input signal, but also reduce the requirement of the system to the random sequence rate, but also can further reduce the sampling rate of the system. In order to eliminate the direct current of light intensity modulation and direct detection, an optical time-domain stretching subsystem based on the balanced structure is proposed, and the signal-to-noise ratio of the signal acquisition is improved. In this paper, three compression-sensing schemes based on microwave-photon filtering are proposed, and the low-pass filtering or accumulation process in the compression perception is realized in the optical domain. In the scheme, a multi-wavelength non-coherent light source and a dispersion medium are utilized, and the accumulation between adjacent bit positions of the random modulation signal is realized under the effect of group velocity dispersion. In the scheme, a single-wavelength continuous light source and a dispersion medium are utilized to realize low-pass filtering of the random modulation signal and simplify the system. According to the scheme, the multi-tap microwave photon filter based on the optical frequency comb-up is realized by the technology of the integrated chip, the sidelobe suppression ratio of the filter response is increased, the error of the signal recovery is reduced, and the system is beneficial to the development of the system in the integrated direction. The performance of wide-band sparse signal acquisition is verified by experiment and numerical simulation.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN911.7
[Abstract]:The acquisition of broadband signals is an essential technology for modern radar, radio astronomy, electronic warfare, and other advanced communication systems. The traditional electric appliance-based signal acquisition has the disadvantages of small bandwidth, large power loss and susceptibility to electromagnetic interference, and the like. The photonics technology has the advantages of large bandwidth, light weight, low loss and anti-electromagnetic interference, and becomes an important development direction of the future broadband signal acquisition. At present, two important technologies based on photonic broadband signal acquisition are photonic analog-to-digital conversion technology and photon compression sensing technology. In this paper, we aim to improve the performance of signal acquisition, including higher precision and larger bandwidth, and propose a wide variety of wideband signal acquisition schemes based on photon analog-to-digital conversion and photon-compression sensing. The paper first introduces the research background, main application direction and important device of microwave photonics. The application of the photon-based analog-to-digital conversion and the photon-compression-sensing based broadband signal acquisition and its advantages over the corresponding electric technology are introduced. Aiming at the problems existing in the prior art, some innovative structures and schemes are put forward, and the system is verified by simulation and experiment. The main innovation points and academic contributions of the paper are as follows:1. By analyzing the limitation of the classical model of the photon analog-to-digital conversion (Taylor's scheme), a photonic analog-to-digital conversion scheme based on differential coding is proposed, and the system is validated by numerical simulation. In the scheme, a phase modulator (PM) and an interferometer are used, and the code of the input signal differential form is realized by combining the wavelength division multiplexing technology, so that the problem that the length of the modulator electrode in the Taylor scheme is doubled is overcome, and the feasibility of the system is improved. In addition, the implementation of differential coding improves the equivalent quantization level of the system. In order to further improve the performance of the system, we use the dual-drive, non-balanced modulator instead of the PM and the interferometer, not only to reduce the volume of the system, to reduce the loss of the system, but also to utilize the integration of the system. On the basis of in-depth study of the coding characteristics of the symphonic digital system (SNS) and the application of the SNS in the analog-to-digital conversion, an improved SNS-based photonic analog-to-digital conversion scheme is proposed. An interferometer with equal half-wave voltage and a plurality of electric comparators are used in the scheme, and the SNS coding with the Gray code property is realized by designing the phase shift between the interferometers, thereby greatly improving the error correction capability of the system. In order to eliminate the influence of the amplitude of the light source, it is proposed to apply the balance detection technique to the system, thus the stability of the system is improved. On the basis of fully understanding the basic principle of the compression perception, the method of theoretical research and numerical simulation is used to analyze the broadband signal acquisition based on the photon-compression perception. The photon compression sensing scheme based on spatial light modulator (SLM) and electro-optical modulator (EOM) is introduced, and the feasibility and problems of the system are verified by experiments. The random modulation method based on the structure of the balanced Mach-Zehnder modulator (MZM) is proposed, the mathematical model of the compression-sensing system is simplified, and the random observation matrix with zero mean value is realized, and the performance of the system is improved. In the compression-aware system, the rate of the random sequence needs to reach the limit of twice the bandwidth of the input signal, and a compression-sensing scheme based on the optical time-domain stretching technology is proposed. The optical time-domain stretching technology makes full use of the group delay caused by dispersion to stretch the radio-frequency signal loaded on the optical signal. The combination with the compression-sensing technology can not only reduce the rate of the input signal, but also reduce the requirement of the system to the random sequence rate, but also can further reduce the sampling rate of the system. In order to eliminate the direct current of light intensity modulation and direct detection, an optical time-domain stretching subsystem based on the balanced structure is proposed, and the signal-to-noise ratio of the signal acquisition is improved. In this paper, three compression-sensing schemes based on microwave-photon filtering are proposed, and the low-pass filtering or accumulation process in the compression perception is realized in the optical domain. In the scheme, a multi-wavelength non-coherent light source and a dispersion medium are utilized, and the accumulation between adjacent bit positions of the random modulation signal is realized under the effect of group velocity dispersion. In the scheme, a single-wavelength continuous light source and a dispersion medium are utilized to realize low-pass filtering of the random modulation signal and simplify the system. According to the scheme, the multi-tap microwave photon filter based on the optical frequency comb-up is realized by the technology of the integrated chip, the sidelobe suppression ratio of the filter response is increased, the error of the signal recovery is reduced, and the system is beneficial to the development of the system in the integrated direction. The performance of wide-band sparse signal acquisition is verified by experiment and numerical simulation.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN911.7
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