【摘要】：近年來,微納波導(dǎo)中光學(xué)特性的研究吸引了越來越多的研究者的注意。而表面等離子體(SPP)在波導(dǎo)中的突出性能:可以突破光的衍射極限將其限制在微納尺度范圍,并能實(shí)現(xiàn)對光場的增強(qiáng)限制,以此可提高非線性相互作用。另外,據(jù)調(diào)研,目前的SPP波導(dǎo)局限在平板波導(dǎo)�；诖�,研究設(shè)計(jì)線性波導(dǎo)并其在通信波段的光學(xué)特性是很有必要的。本文的主要內(nèi)容就是基于表面等離子體的光纖波導(dǎo)中模式特性及其色散調(diào)制的研究。在基礎(chǔ)理論部分,首先簡要回顧了光在波導(dǎo)中傳輸時(shí)存在的幾種色散形式:材料色散、波導(dǎo)色散、模式色散。接著介紹了非線性效應(yīng)中四波混頻的基本原理。在現(xiàn)有理論基礎(chǔ)上,通過對非簡并四波混頻效應(yīng)耦合模差分方程的推到,分析出了實(shí)現(xiàn)高效的波長轉(zhuǎn)換的幾個(gè)關(guān)鍵因素。首先要通過合理的設(shè)計(jì)波導(dǎo)結(jié)構(gòu)實(shí)現(xiàn)進(jìn)行波長轉(zhuǎn)換的對應(yīng)模式間的相位匹配;另一方面要利用具有高的非線性極化張量的介質(zhì)作為非線性相互作用的媒介;最后,要獲得高的非線性系數(shù),還要通過設(shè)計(jì)波導(dǎo)結(jié)構(gòu),獲得小的模場面積積分值。根據(jù)以上分析,對本文提出的金屬-介質(zhì)-金屬波導(dǎo)結(jié)構(gòu)做了相應(yīng)調(diào)整,分別在微米和納米尺度進(jìn)行了模擬分析。據(jù)相關(guān)文獻(xiàn)調(diào)研,表面等離子激子可有效的提高波導(dǎo)結(jié)構(gòu)對光場的限制能力,使非線性效應(yīng)得到增強(qiáng)。文中主要提出并研究了兩種金屬包層的光纖波導(dǎo)結(jié)構(gòu):一種為金屬包層的微光纖;另一種為金屬-介質(zhì)-金屬光纖波導(dǎo)。對于第一種波導(dǎo)模型,文中詳細(xì)分析了不同金屬包層厚度對波導(dǎo)中光場分布,有效模式指數(shù)及傳輸損耗等相關(guān)特性的影響。在此基礎(chǔ)上,通過對波導(dǎo)中模式色散特性的調(diào)制分析,利用模間相位匹配技術(shù),在微光纖半徑1μm附近實(shí)現(xiàn)基頻光與其三次諧波光對應(yīng)模式的相位匹配,且相位匹配點(diǎn)附近,兩模式的有效折射指數(shù)曲線非�？拷�,有利于實(shí)際應(yīng)用中非線性效應(yīng)的實(shí)現(xiàn)。對于金屬-介質(zhì)-金屬這一波導(dǎo)結(jié)構(gòu),分別在微米、納米尺度范圍內(nèi)對其中存在的光波模式、傳輸特性、色散特性及光場的限制能力做了研究。微米尺度上,通過改變不同的結(jié)構(gòu)參數(shù)實(shí)現(xiàn)了對零色散點(diǎn)的調(diào)制。納米尺度上,波導(dǎo)實(shí)現(xiàn)了對光場突破衍射極限的強(qiáng)的場強(qiáng)限制。利用不同波長的光在同一模式上的相位匹配技術(shù),分析了其在四波混頻效應(yīng)中的表現(xiàn)性能。
[Abstract]:In recent years, more and more researchers have paid attention to the study of optical properties in micro / nano waveguides. The outstanding performance of surface plasma (SPP) in waveguide: it can break through the diffraction limit of light to limit it to the range of micro-and nano-scale, and can realize the enhancement limitation of light field, so that the nonlinear interaction can be improved. In addition, according to the investigation, the current SPP waveguide is limited to the flat waveguide. Therefore, it is necessary to study and design linear waveguides and their optical properties in the communication band. The main content of this paper is the study of mode characteristics and dispersion modulation in fiber waveguides based on surface plasma. In the basic theory part, several dispersion forms of light propagation in waveguide are briefly reviewed: material dispersion, waveguide dispersion and mode dispersion. Then the basic principle of four-wave mixing in nonlinear effect is introduced. On the basis of the existing theory, several key factors to realize efficient wavelength conversion are analyzed by deducting the coupled mode difference equation with non-degenerate four-wave mixing effect. Firstly, the phase matching between the corresponding modes of wavelength conversion should be realized through the rational design of waveguide structure, on the other hand, the medium with high nonlinear polarization Zhang Liang should be used as the medium of nonlinear interaction. Finally, in order to obtain the high nonlinear coefficient, we must design the waveguide structure and obtain the small mode field area integral value. According to the above analysis, the structure of the metal-dielectric-metal waveguide proposed in this paper is adjusted accordingly, and the simulation analysis is carried out on the micro-scale and the nano-scale respectively. According to the relevant literature investigation, the surface plasma exciton can effectively improve the limiting ability of the waveguide structure to the light field and enhance the nonlinear effect. In this paper, two kinds of metal-clad optical fiber waveguides are proposed and studied: one is metal-clad micro-fiber, and the other is metal-dielectric-metal fiber waveguide. For the first waveguide model, the effects of different metal cladding thickness on the optical field distribution, effective mode index and transmission loss in the waveguide are analyzed in detail. On this basis, through the modulation analysis of the mode dispersion characteristics in the waveguide, the phase matching between the fundamental frequency light and its third harmonic light near the radius of 1 渭 m is realized by using the inter-mode phase matching technique, and the phase matching point is near the phase matching point. The effective refractive index curves of the two modes are very close to each other, which is beneficial to the realization of nonlinear effect in practical applications. For the metal-dielectric-metal waveguide structure, the optical wave modes, propagation characteristics, dispersion characteristics and the limiting ability of the light field are studied in the micron and nano-scale respectively. On the micron scale, the zero dispersion point modulation is realized by changing different structural parameters. On the nanometer scale, the waveguide realizes the strong field strength restriction to the light field breaking the diffraction limit. By using the phase matching technique of different wavelengths of light in the same mode, its performance in the four-wave mixing effect is analyzed.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN25

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本文編號：2447160