基于组合偏振调制和正交边带处理的高倍频相位调谐毫米波产生技术研究

Millimeter-wave signals possess extensive applications in fields such as radar, remote sensing, and communications. Dealing with the simultaneous realization of high frequency-multiplying and tunable phase shift in photonic generation of millimeter-wave technology, the idea of compound polarization modulation and orthogonally sidebands processing is proposed to generate up to frequency-octupling millimeter-wave with 360 degree tunable phase shift. The theoretical model of high frequency-multiplying millimeter-wave generation based on cascaded or parallelled polarization modulators will be firstly established. The output characteristic and sidebands suppression principle of cascaded or parallelled polarization modulators will be investigated to deliberate the relations between the polarization direction of polarizer, the modulation index of modulator, the phase difference of two input radio frequency signals, and the order of suppressed sidebands. The influences of these factors on optical sidebands suppression ratio and radio frequency spurious suppression ratio will be also discussed. Next, the theoretical model of millimeter-wave generation with tunable phase shift based on polarization-maintaining fiber Bragg grating (PM-FBG) will be established to analyze the influences of the lightwave polarization direction, the length and the birefringence of the FBG, and the fringe visibility on the spectral responses of the PM-FBG. The mechanism and methods of millimeter-wave phase control based on orthogonally sidebands processing will be investigated. The influences of the frequency and power level of input radio frequency signal on the phase of millimeter-wave will be determined. Finally, the simulation model and experimental system will be established to demonstrate the feasibility of compound polarization modulaiton and orthogonally sidebands processing technology. The achievements of the project will provide theoretical basis and technical support for the research and development of next generation phased array radar, satellite remote sensing, and broadband communication millimeter-wave systems.

毫米波信号在雷达、遥感、通信等领域有广泛应用。针对光生毫米波技术中同时实现高倍频和相位调谐问题，提出了基于组合偏振调制和正交边带处理产生最高八倍频、360度相位调谐毫米波的思路。首先，建立级联或并联偏振调制器产生高倍频毫米波的理论模型，研究其输出特性和边带抑制原理，阐明起偏器起偏角、调制器调制系数、输入射频信号相位差与抑制边带阶数之间的关系以及它们对光边带抑制比和射频杂散抑制比的影响。其次，建立基于保偏光纤光栅产生相位调谐毫米波的理论模型，分析输入光波偏振角、光栅长度、双折射和条纹可见度对保偏光纤光栅频谱响应的影响，研究基于正交边带处理的毫米波光子相位控制机制和方法，得到输入射频信号功率和频率对毫米波相位的影响规律。最后，搭建仿真模型和实验系统，验证组合偏振调制和正交边带处理技术的可行性。本项目的研究成果可为下一代相控阵雷达、卫星遥感和宽带通信毫米波系统的研发提供理论基础和技术支撑。

毫米波信号在雷达、遥感、通信等领域有广泛应用。针对光生毫米波技术中同时实现高倍频和相位调谐问题，提出了基于组合偏振调制和正交边带处理产生高倍频、相位调谐毫米波的思路。首先，建立了级联两个偏振调制器和一个双平行偏振调制器产生毫米波信号的理论模型，对比分析了两种方法产生毫米波信号的性能，归纳了光信号偏振态、调制器调制系数、输入微波驱动信号相位差与频率倍频因子之间的关系，阐明了边带抑制原理。实验获得了频率间隔45.6 GHz、光边带抑制比为15.57 dB的八倍频信号、频率间隔34.2 GHz、光边带抑制比为17.16 dB的六倍频信号和频率间隔16 GHz、光边带抑制比为19.13 dB、射频杂散抑制比为21.35 dB的四倍频信号。在此基础上，利用光纤光栅嵌入萨格纳克环产生偏振正交双边带信号。实验获得了频率间隔32 GHz、80 GHz和91.2 GHz的偏振正交四阶光边带以及频率间隔20 GHz的偏振正交二阶光边带。最后，利用偏振调制器为偏振正交光边带引入相位差，在射频驱动信号为7.5 GHz条件下，实验实现了30 GHz微波信号的相位调谐。本项目的研究成果可为下一代相控阵雷达、卫星遥感和宽带通信毫米波系统的研发提供理论基础和技术支撑。