光折变效应特性及其在波分复用技术中的应用

【作者】 林巧文；

【导师】 忽满利；

【作者基本信息】 西北大学 ， 光学， 2007， 硕士

【摘要】 本文通过比较几类WDM复用器件，指出各自的优缺点。基于体光栅严格的波长与角度选择性，提出了一中制作波分复用器的新方法—体全息光栅波分复用法，并就该器件的设计原理、制作方法、等一系列问题展开讨论。其主要内容包括：1．阐述了光折变效应产生的机制和光折变Bragg光栅的形成机理；以体全息光栅的耦合波理论为基础，讨论了光折变晶体中体全息光栅的衍射效率、角度、波长选择性；从Bragg衍射公式出发讨论了体全息Bragg光栅用于波分复用时的波长关系及宽光谱应用时光栅的Bragg失配量。2．从理论上着重探讨了LiNbO₃：Fe：Zn晶体作为波分复用器，其写入角、通道间隔、转动角是互相制约的。另外，对光栅的厚度与最小通道间隔的关系也进行了讨论。3．对晶体中体全息Bragg光栅的写入和擦除时间常数进行了测量，在此基础上对多重光栅的曝光方法进行了讨论。并进一步分析了波分复用器件制作过程中诸如记录材料的选择、写入光路以及曝光方法等关键技术环节，研究表明双掺杂的铌酸锂晶体（LiNbO₃：Fe：Zn）是用于光折变体全息波分复用器件的最佳材料。4．讨论了在双掺杂的LiNbO₃（Fe，Zn）晶体中多重体全息Bragg光栅的写入方法，并提出了基于体全息光栅技术的全息波长解复用器的具体设计方案，在此实验的基础上，对多重体全息Bragg光栅用于波分复用器的可行性进行了验证。在上述的基础上，设计出基于体全息技术的选择型1×2全息光自选通的实验方案，并进行了理论和实验的对比。更多还原

【Abstract】 In this thesis, by contrasting, I indicate some advantages and disadvantages of several kinds of WDM respectively. Based on volume grating having strict wavelength and angle selectivity, put forward a new method of making Wavelength division multiplexing—volume holographic wavelength division multiplex. Meanwhile I discuss some issues about this kind of WDM such as design principal, facture method and its properties.the main contents are as follows:1. The mechanisms of the photorefractive effect and the creation of photorefractive grating are explained .Based on the coupled-wave theory, the Bragg diffraction efficiency, the angle selectivity and wavelength selectivity of volume holographic Bragg gratings formed in photorefractive crystals are analyzed. According to the Bragg’s diffraction formula, the relation of the demultiplexing angle on communication wavelengths to the writing angle of volume holographic Bragg gratings, and the Bragg mismatching value during wavelength demultiplexing with wide spectra by employing volume holographic Bragg gratings are discussed.2. Writing angle, channel space, rotation angle, in LiNbO₃:Fe:Zn crystal as the device of wavelength-division multiplexing, are discussed in theory. And the relation of the thickness of grating and the minimum channel space is discussed, too.3. The holographic time constants were gained by recording and erasing a single grating in a slice of LiNbO₃:Fe:Zn crystal. According to the recording and erasing time constants, the exposure time schedule of superimposed gratings was discussed. The pacing technology in making the WDM device such as selecting recording material, making sure recording geometry , exposure method and so on are analyzed further. The research conclusions are as follows: the Fe and Zn doped LiNbO₃ should be considered at first as holographic recording material in our system.4. The recording approach of the multiple volume holographic Bragg gratings in LiNbO₃:Fe:Zn crystal was investigated. Concretely designing scheme of holographic wavelength demultiplexing based on the technique of volume holographic gratings is put forward. On the base of this experiment, the experiment shows the feasibility of the multiple volume holographic Bragg gratings using in the wavelength division multiplexing.A experimental scheme of selective 1×2 holographic optical self- thoroughfare based on volume holographic grating is designed, and compared the result of the experiment with the theory.更多还原