摘要：
為了研究基于光子晶體波導(dǎo)的高性能濾波器,采用調(diào)節(jié)諧振腔結(jié)構(gòu)和優(yōu)化耦合結(jié)構(gòu)等方法,基于耦合模理論,在正方格光子晶體中設(shè)計了3種光子晶體彎折波導(dǎo),并進行了理論分析和仿真驗證,利用時域有限差分法取得了3種波導(dǎo)在S波段及C波段上的工作特性數(shù)據(jù).結(jié)果表明,3種波導(dǎo)在不同波段表現(xiàn)出良好的帶阻或帶通特性,且其結(jié)構(gòu)截止傳輸波長和通帶傳輸波長隨整體介質(zhì)柱相對介電常數(shù)增加向長波方向移動,介電常數(shù)εr每增加0.3,截止傳輸波長和通帶傳輸波長均增加6nm左右.這一結(jié)果對微型光傳感器、微型光通信器件、集成光路等方面的設(shè)計都是有幫助的.%In order to study high performance filters based on photonic crystal waveguide,some methods such as adjusting the structures of resonant cavities and optimizing the coupling regions were adopted in the paper.Three kinds of bent photonic crystal waveguides were designed based on the coupled-mode theory in square dielectric rod photonic crystal.After theoretical analysis and experimental verification,the performance characteristics in the S-band and C-band were studied by the time-domain finite-different method.The results show that,3 kinds of waveguides have good band stop or band pass characteristics at different wavelengths.Cutoff transmission wavelength and passband transmission wavelength shift toward longer wavelengths with the increase of relative dielectric constant of the overall dielectric column.Cutoff wavelength and transmission wavelength are increased by about 6ran with the increase of dielectric constant εr by 0.3.The study has potential value in the designs of micro optical sensors,micro optical communication devices,optical integrated circuits,etc.
摘要：
為了對折射率型1維光子晶體缺陷波導(dǎo)中的光傳輸進行有效數(shù)值模擬,采用此類型波導(dǎo)的厄米-高斯函數(shù)展開方法進行了研究. 首先給出了計算方法的詳細理論推導(dǎo),然后利用該方法計算了偏振態(tài)不同、結(jié)構(gòu)參量不同的情況下波導(dǎo)本征模式的色散關(guān)系、模場空間分布、能量控制因子及等效折射率. 結(jié)果表明,1維光子晶體缺陷波導(dǎo)與階躍平面光波導(dǎo)主要差別在于高階模式,且可通過調(diào)節(jié)1維光子晶體的結(jié)構(gòu)參量來有效調(diào)控高階模式的傳輸.%In order to simulate the light propagation in 1-D refractive-index-typed photonic crystal ( PC) defect waveguide effectively, Hermite-Gaussian function expansion method was adopted .At first, the detailed theoretical derivations of the calculation method were presented .And then, dispersion relation, mode field patterns, energy control factor and equivalent refractive index of 1-D PC waveguides with different polarizations and different structural parameters were calculated .The results show that there are significant differences in the high-ordered modes between 1-D PC defect waveguides and step planar waveguides .The transmission of high-order modes can be controlled effectively by adjusting the structural parameters of 1-D PC.
摘要：
為了設(shè)計基于光子晶體波導(dǎo)的高性能濾波器件,在2維正方格子光子晶體波導(dǎo)結(jié)構(gòu)中引入一系列齒狀缺陷,采用有限元法對齒狀光子晶體波導(dǎo)的傳輸特性進行了數(shù)值仿真和理論分析. 結(jié)果表明,對于單個齒狀缺陷,缺陷產(chǎn)生的共振頻率使得在光子晶體波導(dǎo)通頻域帶出現(xiàn)帶隙結(jié)構(gòu),可以實現(xiàn)良好的窄帶濾波,并且通過改變齒狀缺陷深度可以有效地控制缺陷的共振頻率;引入多個齒狀缺陷,缺陷之間會經(jīng)過耦合作用形成一系列缺陷態(tài),使得在光子晶體波導(dǎo)導(dǎo)通頻域中出現(xiàn)寬帶的帶隙結(jié)構(gòu),可以實現(xiàn)寬帶濾波. 該光子晶體波導(dǎo)濾波器對窄/寬帶濾波可根據(jù)波導(dǎo)結(jié)構(gòu)中引入的齒狀缺陷進行簡單靈活調(diào)節(jié). 此研究在設(shè)計基于光子晶體波導(dǎo)的光子濾波器件方面具有潛在的應(yīng)用價值.%In order to design high performance filters based on photonic crystal waveguide , new band-stop filter was proposed by introducing a series of tooth-shaped defects into 2-D photonic crystal waveguide .Transmission characteristics of tooth-shaped photonic crystal waveguide were studied by finite element method .The results show that , for single tooth-shaped defect , resonance frequency generated by defect leads to a band-stop structure and good narrowband filter is achieved .Resonance frequency can be modulated by changing the depth of defect .For multiple tooth-shaped defects , due to the coupling effect , a series of defects form a wide band stop of photonic crystal waveguide with relatively wider bandwidth .Photonic crystal waveguide filters can be simple and fiexible adjustment by introducing tooth-shaped defects to achieve narrow/broadband filters .The study has potential value in the design of photonic filter devices based on photonic crystal waveguides .
摘要：
提出了一種基于六角格子光子晶體波導(dǎo)微腔和Fabry-Perot (FP)腔非對稱耦合的全光二極管結(jié)構(gòu)，它由一個包含非線性Kerr介質(zhì)的高Q值微腔與一個光子晶體波導(dǎo)中的FP腔組成。通過有限時域差分方法對其傳輸特性進行了仿真，發(fā)現(xiàn)通過兩腔的非對稱耦合可以實現(xiàn)在特定光強度下的正向傳輸、反向截止的功能。在靠近微腔方向光入射時，特定強度的光可以激發(fā)非線性微腔的Kerr效應(yīng)，改變了Fano腔的共振頻率，從而變成透射狀態(tài)。而遠離微腔方向光入射，由于這個不對稱的結(jié)構(gòu)造成場局域的分布不對稱，激發(fā)微腔Kerr效應(yīng)的光強還不夠，所以光不能透射。所設(shè)計的全光二極管結(jié)構(gòu)具有良好的性能參數(shù)：最大透射率高和高透射比、光強閾值低和易于集成等。%A high e?ciency all-optical diode based on 2D hexagonal lattice photonic crystal (PC) waveguide is proposed. The structure is asymmetrically coupled by a high Q factor micro-cavity-containing nonlinear Kerr medium and a Fabry-Perot cavity in PC waveguide. The transmission properties are numerically investigated by finite-difference time-domain (FDTD) method. Because of interference between the two cavities, the structure can achieve the function of forward transmission and backward cut-off under a suitable light intensity. For light incidence close to the direction of micro-cavity, nonlinear Kerr effect of micro-cavity can be excited by a certain light intensity. Then the resonant frequency of Fano cavity will change and forward incidence becomes transmission from reflective state. But for light incidence away from the direction of micro-cavity, the field distribution is asymmetric due to the asymmetric structure, so backward incidence needs stronger incidence light to excite Kerr effect and keeps reflective state. This design of all-optical diode has many advantages, including high maximum transmittance, high transmittance contrast ratio, low power threshold, and ease of integration, and so on.
摘要：
The transmission and frequency characteristics of the micro-laser with photonic crystal waveguide were analyzed in this paper based on the finite-difference-domain (FDTD) method. The results demonstrate that, compared with the pure random media or pure photonic crystal waveguide, the light in defect area with random media is obviously amplified, meanwhile the localization level becomes higher either. On the other hand, the interaction time between the random gain medium is prolonged, the loss and the threshold is reduced. In addition, the light can be modulated by the triangle lattice photonic crystal. The design of new device in this paper lay a theoretical foundation of integrated optical system and micro-laser with low threshold.%文中采用有限時域差分(FDTD)法研究了ZnO隨機介質(zhì)與光子晶體波導(dǎo)相結(jié)合的微型激光器的輻射特性和頻譜特性，用平面波展開法分析了光子晶體能帶特性。數(shù)值研究結(jié)果表明：由于光與隨機介質(zhì)相互作用，使得光在該微型激光器中放大，損耗減小，存在較長滯留時間，同時隨機介質(zhì)局域光的能力變強，激光的閾值降低，而且含四方格子結(jié)構(gòu)光子晶體的激光器具有良好的激光特性和調(diào)制作用。該新型器件的設(shè)計與研究將為研制可嵌入集成光子芯片的、低閾值的微型激光器提供理論基礎(chǔ)。
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