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.     

光子晶体在光通信中的应用

妻亨首先介绍了新型材料光子晶体的基本特点,然后探讨了含有光子晶体的光器件在光通信系统中的各种应用。     

复式晶格光子晶体多波长THz光开关

THz(太赫兹)通信在高速、超宽带的无线接入网中有着重要的应用。THz光开关是THz通信的关键器件之一,对其进行研究具有重要意义。文章设计了一种新型的基于复式晶格光子晶体的多波长THz光开关,它能够有效地实现四波长THz波的开、关控制。利用RSOFT软件中的FDTD(有限差分时域)方法进行了仿真,结果表明,该开关的消光比达40dB,插入损耗为0.109dB,开关速率为5.55GHz,在未来无线光通信方面有着重要的应用潜力。     

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.     

光子晶体光纤在光纤通信中的应用

文章综述了光子晶体光纤的结构、导光原理和特性及其在光纤通信中的应用前景。     

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.     

硫系玻璃超快光子晶体光开关特性研究

利用熔融淬冷法制备了GeSbSe硫系玻璃,并用Z 扫描法测试了其三阶非线性特性。以制备的硫系玻璃作为基质材料设计了通信波段的光子晶 体光开关器件,采用平面波展开法优化了光子晶体结构的带隙,利用时域有限差分(FDTD)法 分析了所设计的光子晶体光开关结 构的传输特性,通过调整晶格常数与点缺陷的半径,获得了在超短激光脉冲诱导下的硫系玻 璃超快光子晶 体光开关。数值计算表明,对于1550 nm通 信波段,通过调节泵浦光强并使微腔处折射率改变,可以 实现对光波的导通与截止。分析结果显示,本文光开关的 阈值功率密度为7.7×10⁹W/cm²,开关消光比为25.48dB,品质因子达到10⁴。     

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.     

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.     

A near infrared optical reflector using one-dimensional photonic crystal structure containing chalcogenide glasses

The reflectivity of one-dimensional chalcogenide photonic crystal (CGPC) structure with the first order reflection band in near infrared (NIR) region is theoretically studied. Sb-Se and Ge-S chalcogenide glasses are used as high and low refractive index layers respectively, because these materials have zero absorption in NIR region. The transfer matrix method (TMM) is employed to calculate the reflective spectra of the proposed structure. The theoretical results of reflective spectra of bulk chalcogenide materials with the composition of Sb₄₀Se₆₀ and Ge₃₀S₇₀ for 4, 8, 12 and 15 layers and thicknesses of 117 nm and 183 nm respectively, at normal incidence, are close agreement with the experimental results. Furthermore, by increasing the number of layers of Sb₄₀Se₆₀ and Ge₃₀S₇₀, the reflection bands can be enhanced in the wider range of the NIR region for the polarization at different angles and thus the broadband omnidirectional reflector can be designed.     

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。     

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.     

介质光学厚度对光子晶体透射谱特性的调制

利用传输矩阵法理论,研究介质光学厚度对一维光子晶体(AB)5(BA)5透射谱特性的影响,结果表明:只要A、B介质光学厚度满足DA=DB,随着介质光学厚度的增大,光子晶体透射峰的透射率、频率位置和带宽均保持不变;当A、B介质的光学厚度不相等即DA≠DB时,随着DA或DB,或DA、DB的增大,禁带中透射峰的透射率不变但带宽变宽,且当DADB时透射峰向高频方向移动,反之则向低频方向移动。介质光学厚度对光子晶体透射谱的调制规律,可为光子晶体模型的构建、窄带光学滤波器和光学开关的设计等提供有益参考。     

Demonstration of multi-core photonic crystal fibre in an optical interconnect

A novel microstructured fibre has been created for use in an optical interconnection system. The fibre has low crosstalk with a high density of cores corresponding to 1150 channels/mm/sup 2/. A repeating pseudorandom binary sequence has been used to demonstrate a four-channel transmit/receive system using vertical cavity surface emitting lasers as both emitters and detectors.     

四元异质结构光子晶体的双通道光学滤波特性

为了设计高品质的光学滤波器,采用传输矩阵法研究四元异质结构光子晶体（ABC）7D（CBA）7的双通道光学滤波特性。结果表明,随着A（或C）介质薄膜光学厚度D_A（或D_C）的增大,滤波器短波通道的滤波品质因子降低,长波通道的滤波品质因子升高;随着B介质薄膜光学厚度D_B增大,滤波器短波通道和长波通道的滤波品质因子均下降;随着D介质薄膜光学厚度D_D增大,滤波器短波通道的滤波品质因子升高,而长波通道的滤波品质因子降低;随着各薄膜介质层光学厚度增大,滤波器双通道均向长波方向红移,但各滤波通道的光透射率均保持100%不变。该研究结果可为光子晶体设计新型光学滤波器件、光学开关等提供参考。     

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     

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.