基于微波光子学的微波信号生成技术研究

发布时间：2018-08-11 10:07

【摘要】：微波光子学是一种利用光学方法产生、传输、处理微波信号的新型技术。相对于传统电子技术,微波光子技术具有低损耗、大带宽、体积重量小、抗电磁干扰等优势。微波信号的光学产生技术是微波光子学中一个重要的研究内容。在本论文中,我们对以下两个方面进行了重点研究:1、基于微波光子学的微波本振倍频技术;2、基于微波光子学的三角波信号生成技术。本文首先介绍了几种常用的电光调制器,并对其结构和工作原理进行了理论分析;在对MZM介绍的基础上,利用VPI软件对双边带(DSB)、单边带(SSB)以及抑制载波双边带(OCS-DSB)三种调制方式做了仿真分析;介绍了光谐波抑制比(OSSR)、电谐波抑制比(RFSSR)以及相位噪声这三个性能指标的定义。其次,本文研究了一种基于双偏振-正交相移键控(DP-QPSK)调制器的微波信号光学八倍频方案,并对该方案进行了仿真分析和实验验证。实验结果中各个性能指标为:光谐波抑制比为10.28dB;电谐波抑制比为12.68dB;各个频偏处相位噪声恶化约为18dB,与理论推导结果一致。该方案由于没有用到任何光滤波器或者电滤波器,不仅简化了电路、易于操作,最重要的是该方案的频率可调谐性很好。实验过程中利用3GHz、4.5GHz、5GHz以及6GHz四个频率的射频信号进行了倍频实验,得到了较为理想的光谱。论文同时研究了一种利用相位调制器(PM)及光纤布拉格光栅(FBG)生成三角波信号的方案,并对该方案进行了仿真分析。仿真中采用3GHz驱动信号对光载波进行相位调制,当FBG对光载波和正一(或负一阶)光边带抑制比均为6dB,调制指数设置为0.68时,拍频后二次谐波被抑制,且一次谐波与三次谐波的功率差为19.12dB(一次谐波和三次谐波的幅度比为9:1),产生了重复频率为3 GHz的三角波信号;当FBG对光载波和正一(或负一阶)光边带抑制比均为4dB,调制指数设置为0.75时,拍频后二次谐波被抑制,且一次谐波与三次谐波的功率差为19.06dB(一次谐波和三次谐波的幅度比为9:1),产生了重复频率为3GHz的三角波信号。
[Abstract]:Microwave photonics is a new technique to produce, transmit and process microwave signal by optical method. Compared with traditional electronic technology, microwave photonic technology has the advantages of low loss, large bandwidth, small volume and weight, anti-electromagnetic interference and so on. The optical generation technology of microwave signal is an important research content in microwave photonics. In this thesis, we focus on the following two aspects: 1, microwave local oscillator doubling technology based on microwave photonics, and triangle wave signal generation technology based on microwave photonics. In this paper, several common electro-optic modulators are introduced, and their structure and working principle are analyzed theoretically. Using VPI software, three modulation modes of (DSB), single sideband (SSB) and suppression carrier two-sided band (OCS-DSB) are simulated and analyzed, and the definitions of three performance indexes, namely, optical harmonic suppression ratio (OSSR), electric harmonic suppression ratio (RFSSR) and phase noise, are introduced. Secondly, an optical octave scheme of microwave signal based on dual polarization-orthogonal phase shift keying (DP-QPSK) modulator is studied, and the simulation analysis and experimental verification of the scheme are carried out. The experimental results show that the photoharmonic suppression ratio is 10.28 dB, the electric harmonic suppression ratio is 12.68 dB, and the phase noise deterioration at each frequency offset is about 18 dB, which is consistent with the theoretical results. Because no optical filter or electric filter is used in this scheme, it not only simplifies the circuit, but also makes it easy to operate. The most important thing is that the frequency tunability of the scheme is very good. In the process of the experiment, the frequency doubling experiments are carried out using the radio frequency signals of 3 GHz, 4.5 GHz and 5 GHz and four frequencies of 6GHz, and the ideal spectrum is obtained. At the same time, a scheme of generating triangular wave signal using phase modulator (PM) and fiber Bragg grating (FBG) (FBG) is studied, and the scheme is simulated and analyzed. In the simulation, the 3GHz driving signal is used to phase modulate the optical carrier. When the suppression ratio of the FBG to the optical carrier and the first (or negative) optical side band is both 6dBand the modulation index is set to 0.68, the second harmonic is suppressed after the beat. The power difference between the first harmonic and the third harmonic is 19.12dB (the amplitude ratio of the first harmonic to the third harmonic is 9:1), and the triangle wave signal with repetition frequency of 3 GHz is produced. When the FBG to the optical carrier and the positive (or negative first order) optical sideband suppression ratio is 4 dB, the modulation index is set to 0.75, the second harmonic is suppressed after beat frequency. Moreover, the power difference between the first harmonic and the third harmonic is 19.06dB (the amplitude ratio of the first harmonic to the third harmonic is 9:1), and the triangle wave signal with repetition frequency of 3GHz is produced.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN015;TN761

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