三维光子晶体中的缺陷研究

利用传输矩阵方法研究面心立方结构的三维光子晶体,分析了当其分别存在点缺陷、线缺陷、面缺陷时的传输特性变化,发现当引入点、线、面缺陷后,光子晶体中出现缺陷模,进一步数值计算研究表明缺陷模的出现频率和透过率等特性与缺陷介质球的半径、介电常数和缺陷出现的位置等诸多因素有关,这些结果将有助于光子晶体波导、滤波器等器件的设计和应用.     

Ultra-compact optical filter in two-dimensional photonic crystal

A design of an ultra-compact in-plane optical add/drop filter is proposed. The filter is formed by two waveguides and one two-mode cavity in a two-dimensional triangular photonic crystal. The simulated results demonstrate good transfer characteristics with a quality factor of about 1700.     

Photoluminescence of ZnO infiltrated into a three-dimensional photonic crystal

The effect of the photonic band gap (stopband) of the photonic crystal, the synthesized SiO₂ opal with embedded zinc oxide, on its luminescence in the violet spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra of the infiltrated opal depends on the diameter of the constituent nanoglobules, the volume fraction of zinc oxide, and on the signal’s acceptance angle. It is found that, for the ZnO-opal nanocomposites, the emission intensity is decreased and the luminescence decay time is increased in the spatial directions, in which the photonic band gap coincides in spectral position with the luminescence peak of zinc oxide. The change in the decay time can be attributed to the change in the local density of photonic states in the photonic band gap.     

基于Y缺陷的改进型光子晶体光分路器

提出一种Y缺陷的改进型光子晶体光分路器,以提高输出端的透射率。在完整的二维光子晶体中引入线缺陷,构成1×4的Y型光子晶体光分路器。通过调节第一分支处的4个介质柱的半径,使其每个输出端口具有更高的透射率。同时,通过改变第二分支处的1个介质柱的半径,可以实现输出端口的高透射率和输出光能量的灵活调节。Y缺陷光子晶体光分路器可以广泛应用于未来的光路集成、集成光学、微光信息处理和光通信领域。     

Suppression of total radiant flux by three-dimensional photonic crystal coatings

By using three-dimensional photonic crystal coatings fabricated by self-assembly of colloidal microspheres, a new method of controlling thermal radiation is presented. It is found that the total radiant flux emitted by a thermal radiation source is suppressed within a photonic bandgap regime by covering the source with the coating.     

Design and fabrication of silicon photonic crystal optical waveguides

We have designed and fabricated waveguides that incorporate two-dimensional (2-D) photonic crystal geometry for lateral confinement of light, and total internal reflection for vertical confinement. Both square and triangular photonic crystal lattices were analyzed. A three-dimensional (3-D) finite-difference time-domain (FDTD) analysis was used to find design parameters of the photonic crystal and to calculate dispersion relations for the guided modes in the waveguide structure. We have developed a new fabrication technique to define these waveguides into silicon-on-insulator material. The waveguides are suspended in air in order to improve confinement in the vertical direction and symmetry properties of the structure. High-resolution fabrication allowed us to include different types of bends and optical cavities within the waveguides.     

Ultra-high-Q optical filter based on photonic crystal ring resonator

In this study, a photonic crystal ring resonator with a triangular lattice is used to design an optical filter. The proposed structure is able to filter the central wavelength of 1548 nm with a transmission coefficient of over 95%. Moreover, this structure has an ultra-high-quality factor (Q) of about 1290. With altering the features of the structure including the refractive index, the lattice constant and the radius of the rods in the resonator core, their effects on the central wavelength of the filter, transmission coefficient, quality factor and bandwidth are investigated. The plane wave expansion and finite-difference time-domain methods are used to extract photonic band gap and investigate the photonic behavior of the proposed structure, respectively.     

A new proposal for eight-channel optical demultiplexer based on photonic crystal resonant cavities

In this paper, we used the novel defective resonant cavities to design an eight-channel photonic crystal demultiplexer. We showed that by choosing appropriate values for the width of the resonant cavity, the desired wavelengths can be separated. The proposed platform has a square lattice of dielectric rods immersed in air. The value of transmission efficiency for channels was obtained in 94\(-\)99 % range. In addition, the maximum value of crosstalk and average quality factor for channels were calculated –11.2 dB and 2200, respectively.     

光子晶体及其在光通信中的应用研究

介绍了光子晶体的概念,分析了光子晶体在光通信中的主要应用,讨论了光子晶体光纤的光传输性质以及由光子晶体构造的光通信器件,指出了光子晶体对未来光通信技术发展的重要意义。     

All optical half adder based on photonic crystal resonant cavities

In this paper, we are going to propose and design an all optical half adder based on photonic crystal structures. For realizing the proposed structure, we will use two nonlinear resonant cavities inside a two-dimensional photonic crystal structure. Nonlinear resonant cavities will be created by replacing the ordinary rods via defect rod made of nonlinear material such as doped glass. Plane-wave expansion and finite difference time domain methods will be used for simulating the proposed structure. For the proposed structure, the maximum delay time is about 3 ps.     

水下光通信光子晶体多峰滤波器的研究

利用传输矩阵法设计了蓝绿波段的光子晶体多峰滤波器,并研究了影响多峰滤波器的多种因素.结果表明:适当选取光子晶体结构参数,可将透射波段波长移到蓝绿光波段,设计出多峰光子晶体滤波器,适用于多路信号同时传输或双向同时传输.通过对双峰滤波器的优化,可设计出窄带双峰光子晶体滤波器,使多路信号之间干扰小,信噪比也得到改善.     

Properties of the slab modes in photonic crystal optical waveguides

We show that by placing a slab of semiconductor material between two photonic bandgap (PBG) mirrors, waveguide modes at frequencies out of the PBG can be obtained. These modes are similar to the modes of a conventional dielectric slab waveguide. Using these modes, we can obtain very good coupling between a PBG waveguide and a dielectric slab waveguide with similar slab properties. We discuss the properties of these slab modes and outline the guideline for the optimization of the PBG waveguides based on these properties     

Dispersion-flattened Bragg photonic crystal fiber for large capacity optical communication system

A novelty dispersion ultra-flattened Bragg photonic crystal fiber (PCF) has been fabricated in this paper.The fiber is composed of compound cores and periodical claddings with 11 coaxial rings.It has flattened dispersion of 8.54±1.3 ps-(nm· km)-1 in the communication wavelength range of 1460-1625 nm.Its dispersion slope alters from -0.0428 to 0.0392ps·nm-2·km-1.The low attenuation of 0.52 dB/km and low bending loss of 0.09 dB at 1550 nm of the fiber are also achieved.The Bragg PCF has enormously potential application in the fields of dense wavelength division multiplexing systems because of its superior dispersion properties and easy splicing performances.     

材料特性对金刚石结构三维光子晶体带隙特性的影响

应用平面波展开法研究了ZnO、ALAs、CaP和HgTe四种材料构成金刚石三维光子晶体形成的带隙结构,结果发现随着四种材料的折射率和介电常数增加,带隙宽度也逐渐增加,高介电常数的材料容易形成较宽的光子晶体带隙,研究结果为金刚石结构三维光子晶体的制备提供参考.     

实现高效光传输功能的一维光子晶体透射谱

为设计新型高效光学滤波器、放大器,用传输矩阵法理论对一维光子晶体((AB)5C2(BA)5)m的光传输特性进行了研究,结果发现:在实介电常量情况下,光子晶体透射谱出现m条窄带共振透射峰,实现可调性多通道光学滤波功能.当C层为含负虚部的复介电常量(介质中掺入增益性杂质)时,仅在归一化中心频率1.0ω/ω0处出现一条超窄带...     

光子晶体光纤与光通信相关的奇异色散特性

文章首先阐述光予晶体光纤奇异色散特性的物理成因和理论研究方法,然后重点说明和光通信系统应用领域相关的3种色散特性：短波零色散、近零超平坦色散和能够高效地补偿标准单模光纤正色散的高负色散。     

基于光子晶体多模波导的1．31／1．55μm双波长功分器的设计

设计了一种基于光子晶体多模波导的双波长光功分器,该器件能同时实现1.31 μm和1.55μm两种通信波长的光信号功率的平均分配,整个器件长度仅为15μm,是已报道的常规结构的182分之一.根据导模传输法,讨论了对称入射时光子晶体多模波导中的自映像效应,采用时域有限差分法模拟了光场在波导中的分布,入射场的单重像和二重像交替在波导中周期性地出现.并讨论了功分器的输出效率,及输出效率随位于单模波导与多模波导联结处的介电柱位置变化而产生的变化.     

改进的快速评估实际光子晶体光纤特性的方法

将数字信号处理技术和有限元方法相结合,提出了一种改进的快速评估实际光子晶体光纤特性的方法。针对光纤截面的数字图像中出现空气孔断裂的情况,应用数字化的方法自动检测断裂的空气孔边缘,并采用边缘生长方法自动连接断裂的空气孔,以重建用于光子晶体光纤分析的光纤截面信息。在此基础上,结合有限元方法实现了对实际光子晶体光纤特性的快速评估。结合已有的商用的光子晶体光纤对提出的改进方法进行了验证,结果表明:该方法可以有效、快速评估光子晶体光纤的特性,为一些复杂的难以测量光纤特性的评估提供了一种有效方法。