基于SBS的可调谐带通微波光子滤波器的研究

发布时间：2018-03-29 11:19

本文选题：微波光子滤波器　切入点：可调谐　出处：《天津理工大学》2017年硕士论文

【摘要】：微波光子学是研究微波和光波相互作用的交叉型学科,融合了微波学和光子学两门学科的优势,近年来取得了卓越的进步。微波光子滤波器的功能是抑制噪声并滤除杂波信号,仅使所需频段的微波信号通过。它通过光子学的方法来处理传统微波领域的信号,最终构建了具有带宽大、传输损耗低、处理速度快、抗电磁干扰等诸多优势的新型光电复合系统。微波光子滤波器的优势在于它既打破了电子瓶颈的限制,又弥补了电学滤波器的不足之处,有着可调谐、可重构等优良特性,因而备受关注,在毫米波通信、高性能雷达、光载无线通信系统和无线局域网络中具有广泛的应用。为了提高滤波器的调谐范围,本文提出了一种通带可变的微波光子滤波器,该方案基于受激布里渊散射效应并使用两个调制器与一个光纤布拉格光栅生成两个泵浦信号。通过分别调节这两个调制器的调制频率,可以得到双通带滤波器、通带间隔可变的四通带滤波器。而且在两泵浦频率差值不变的情况下,通过调节泵浦信号频率的大小,可以实现滤波器中心频率的超大范围的连续调谐。文中通过仿真模拟了两个泵浦信号的频率大小及其之间的差值对滤波器通带数目、间隔以及中心频率的影响,并讨论了滤波器的带宽与泵浦的功率和受激布里渊散射效应增益介质长度之间的关系。为了使滤波器在调谐的同时保持稳定的频率响应,本文提出了一种工作带宽不受Bf限制的具有360?相移的可调谐相移器结构,并在此基础上提出了一个多抽头的的复系数微波光子滤波器结构,通过分别调节每个光路上的信号发生器改变泵浦光的频率,以获得所需相移量,进而使得微波光子滤波器通带中心频率可调谐。当相移量从负180度至180度变化时,滤波器可以实现在整个自由频谱范围内的连续调谐。由于引入的相移与射频信号无关,因此在整个调谐的过程中,滤波器的频率响应始终保持不变。
[Abstract]:Microwave photonics is an intersecting subject to study the interaction between microwave and photonic waves, which combines the advantages of microwave and photonics, and has made remarkable progress in recent years. The function of microwave photonic filter is to suppress noise and filter clutter signals. Only the microwave signal of the required frequency band is passed through. It processes the signal in the traditional microwave field by photonics, and finally it has the advantages of large bandwidth, low transmission loss and fast processing speed. The advantage of microwave photonic filter is that it not only breaks the limitation of electronic bottleneck, but also makes up for the deficiency of electric filter, and has excellent characteristics such as tunable, reconfigurable, etc. Therefore, it is widely used in millimeter wave communication, high performance radar, optical wireless communication system and wireless local area network. In order to improve the tuning range of filter, a microwave photonic filter with variable passband is proposed in this paper. Based on the stimulated Brillouin scattering effect, two pump signals are generated by using two modulators and a fiber Bragg grating. By adjusting the modulation frequencies of the two modulators, a double-pass band filter can be obtained. A four-pass band filter with variable pass-band intervals. And when the difference between two pump frequencies is constant, by adjusting the size of the pump signal frequency, In this paper, the effects of the frequency size of two pump signals and the difference between them on the number, interval and center frequency of the filter are simulated. The relationship between the bandwidth of the filter and the pump power and the gain medium length of stimulated Brillouin scattering effect is discussed. In this paper, we propose a working bandwidth with 360? Based on the phase shift tunable phase shifter structure, a complex coefficient microwave photonic filter structure with multiple taps is proposed. The frequency of the pump light is changed by adjusting the signal generator on each optical path, respectively, to obtain the required phase shift. Furthermore, the central frequency of microwave photonic filter is tunable. When the phase shift varies from minus 180 degrees to 180 degrees, the filter can achieve continuous tuning in the whole free spectrum. The introduced phase shift is independent of radio frequency signal. Therefore, the frequency response of the filter remains unchanged throughout the tuning process.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN713

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