可重构微波光子滤波器

【作者】 张梅；

【导师】 邱琪；

【作者基本信息】 电子科技大学 ， 光学工程， 2011， 硕士

【摘要】 微波光子滤波器具有损耗低、高带宽、抗电磁干扰以及能够克服电子瓶颈等独有的优点,实现了在光域内对微波信号进行滤波的要求,是微波光子学研究领域中至关重要的器件,并受到许多学者的广泛关注。随着信息技术的发展,人们对微波载波的频率、通信带宽、服务质量的要求更高,使得成本也相应的增加,为了解决这一矛盾,于是将有线(光纤)通信和无线通信相结合的Radio Over Fiber (ROF)技术被提出,此技术具有很好的应用前景。目前国际上的研究集中在设计新型滤波器结构以实现Q值更高的频率响应、负抽头系数、可调性、可重构和更大的动态范围等。本文重点研究了基于可重构性微波光子滤波器结构的设计及其应用。论文的主要工作内容如下:1、论文综述了微波光子滤波器的研究背景及意义,简单说明了其国内外研究动态,并介绍了微波光子滤波器的应用。2、研究可重构微波光子滤波器的理论基础,包括基本理论及级联理论;分析滤波器在光域和电域上的局限性,从这些局限性入手可以研究滤波器的特性;分析可重构微波光子滤波器各类结构的优缺点,通过分析比较为设计可重构微波光子滤波器结构打下基础。3、在举例的两类可重构微波光子滤波器基础上,提出一种基于级联结构的可重构的非相干微波光子滤波器。这种结构的抽头数可以改变,光栅对的反射率分别为0.5和0.99,中心波长1552nm,带宽为1nm,EDF长度取25cm。利用一对光纤光栅来提高Q值,调节光栅对之间掺饵光纤的增益来改变权重,也就是抽头系数,另外基于基本原理结构,改变每条支路上的系数也能实现重构性。这种级联结构,可以快速实现重构性,并能获得高的Q值,自由频谱范围也可以调节。4、详细介绍了ROF系统,并将此可重构微波光子滤波器应用在ROF系统中,可以进行选频,使用的两个光栅的中心频率193.1THz处,反射率分别为0.5和0.99,3dB带宽取125GHz,EDF的长度取15cm,调节泵浦光功率到90mW得到EDFA的增益为1.42的6抽头和15抽头的可重构微波光子滤波器。另外也可以用来得到倍频信号,使用和选频相同光栅对参数的6抽头和9抽头级联可重构微波光子滤波器。在本节的最后还介绍了其他结构的可重构微波光子滤波器在信道抑制、信道选择方面的应用。更多还原

【Abstract】 The microwave photonic filter (MPF), which can process microwave and radio frequency signals directly in optical domain, is an important device in the filed of microwave photonics. Due to its low loss, high bandwidth, immunity to electromagnetic interference and it can overcome the electronic bottleneck and so on, it has attracted wide public concern. The current international research focused on the design of the new filter structure for a higher Q factor of the frequency response, negative coefficients, tunability, reconfigurability and larger dynamic range. With the development of communication technology, the demands in the frequency of microwave carrier, communication bandwidth and the quality of services increases, result in an increasing cost of the wireless communication system. Radio over Fiber technology, which is constituted by wired technique and wireless technique, appears to be a promising solution to overcome this problem, and has good application prospects. In this thesis, a novel reconfigurable MPFs is designed and the respective applications are analyzed.1. The research background and applications of MPF are briefly introduced.2. The principles of reconfigurable MPF, which includes basic and cascaded theory, are studied. In optical domain and electrical domain, the limitations of MPF are analyzed. The characteristics of filter can be studied by these limitations. The advantages and disadvantages of different kinds of reconfigurable structures are analyzed, which leads to some design rules for a reconfigurable MPF.3. Based on cascaded theory and two types of reconfigurable MPFs, a novel reconfigurable MPF is proposed. It’s a incoherent MPF. The number of taps are adjustable, two uniform FBGs centered at 1552 nm of a 1 nm bandwidth, with 50 and 99.9% reflectivities, respectively. The long of EDF is 25 cm. A pair of Fiber Bragg Gratings(FBGs) are used to improve the filter Q value. The weight of tap is changed by the gain of Erbium-Doped Fiber (EDF) and the coefficients of every taps. The novel frame can be rapidly reconfigured for a high Q value and the Free Spectral Range(FSR) is tunable.4. The designed MPF is tested in a ROF simulation system. The double signal can be obtained by the reconfigurable MPF of Cascade structure of 6-tap and 15-tap and the desired signal frequency is selected by the reconfigurable MPF of Cascade structure of 6-tap and 9-tap. This MPF contains two uniform FBGs ,EDF and taps.The two uniform FBGs centered at 193.1THz of a 125GHz bandwidth, with 50 and 99.9% reflectivities, respectively. The long of EDF is 15 cm and the pump laser power is 90 mW. The thesis also analyzed the improvement of another reconfigurable MPF for channel rejection and channel selection in Universal Mobile Telecommunications System(UMTS).更多还原