基于夹层氮化硅波导的可见-中红外超连续谱特性研究

提出一种低厚度氮化硅-蓝宝石-氮化硅夹层波导结构。利用其色散波辐射现象和中红外相位匹配条件,结合波导脉冲传输模型,讨论了夹层波导不同物理尺寸对相位匹配点和光谱展宽的影响,数值模拟获得了0.5~4 μm的超连续谱展宽,并且在-40 dB水平下具有更远中红外色散波产生。通过该模型,详细解释了非线性波导脉冲传输的潜在机制。理论模型分析表明,通过优化氮化硅及蓝宝石夹层的物理尺寸,进而改变相位匹配条件,可以在较宽的波长范围内控制色散波的位置。     

环形结构塑料光子晶体光纤色散特性分析

利用有限差分光束传播法模拟了光波在环形结构塑料光子晶体光纤内的传输情况,讨论了基模有效折射率与光纤结构的关系,并分析了色散特性随孔间距、孔大小变化的一般规律,发现塑料光子晶体光纤的总色散主要来自材料色散,尤其在短波长范围内材料色散更是居于主导地位,但随波长的增大波导色散逐渐增大,可以设计零色散波长位于可见光波段的塑料光子晶体光纤,此光纤也能很好地应用到非线性领域.     

面向中红外应用的硅基光电子学最近研究进展

随着信息传递、处理以及存储能力要求的不断提升,传统的近红外通信波段已呈“容量紧缩”之势。而工艺与CMOS兼容、结构简单、成本低廉的硅基光电子技术在中红外信号传输和处理方面已经显示出独特优势,有望在中红外波段实现大规模集成,在非线性光学等领域实现新的飞跃。首先介绍了硅基光电子技术在中红外应用中的优势以及目前研究过程中所遇到的困难和挑战;其次结合材料属性和结构特性对一些基本元件（如波导、分束/合束器、二极管）等在中红外领域的最新研究成果进行了介绍;最后对近5年来在中红外波段所实现传感应用的非线性光学硅基器件（基于FWM的非线性光学器件、频率梳）和面向中红外通信应用的激光器、调制器、光电探测器进行了成果介绍,并对研究进展进行了总结。     

铋酸盐玻璃高双折射大负色散微结构光纤设计

设计了一种基于36Bi₂O₃-30GeO₂-15Ga₂O₃-10BaF₂-9Na₂O玻璃的可在～3μm波段同时实现高双折射和大负色散的微结构光纤,该光纤结构包括空气孔呈矩形排列的内包层和空气孔呈正六边形排列的外包层。运用全矢量有限元法结合完美匹配层边界条件,从理论上研究了光纤波导结构参数对光纤双折射特性和色散特性的影响。结果显示:在波长2740 nm处,当微结构光纤的结构参数为外包层孔间距Λ_out=1.5μm,外包层占空比d_out/Λ_out=0.68,内包层占空比d_in/Λ_in=0.86,Λ_out/Λ_in=3时,光纤基模的双折射值达到0.0296,x方向偏振基模的色散系数可达-3204.75 ps·nm^-1·km^-1。结果表明,所设计光纤对...     

高阶轨道角动量传输光纤设计及传输特性研究

为解决一般轨道角动量传输光纤传输轨道角动量模式数量少、质量差的问题,提出了一种基于正六边形空气孔排列的新型光子晶体光纤结构。该光纤引入了空气填充率高的矩形空气孔以及采用高折射率材料填充环形传输区域,能够有效提高环形传输区域和包层间的折射率差,且正六边形排列空气孔有利于提高模间有效折射率差。经过结构优化得到最优光纤结构,有限元法的分析结果表明,最优结构下,该光纤在常用波段S+C+L+U波段上能够支持142种轨道角动量模式的传输,最高阶数达到36阶。且所提出光纤具有良好的传输特性,本征模式的最高限制性损耗为10^-9 dB/m量级,与典型轨道角动量传输光子晶体光纤相比至少降低了一个数量级;最大有效模场面积能够达到206.18μm²,最小非线性系数低至0.397 W^-1·km^-1;色散平坦且最小色散变化低至1.457 8 ps/(nm·km);所有本征模式纯度均在93.4%～96.8%范围内。且该光纤具有较好的制备可行性,对制造精度要求不高。因此,该光纤在基于轨道角动量光纤的复用系统中具有广阔的应用前景,为...     

C+L波段色散补偿光纤及模块的研制

波分复用(WDM)传输系统工作波段已经覆盖了C波段和L波段．工作在C L波段的色散补偿模块及色散补偿光纤的研制是通信器件开发的一个重要领域．文章分析了C L波段色散补偿光纤的波导结构,并采用PCVD工艺研制成功了C L波段色散补偿光纤,该光纤可以同时对工作在C和L波段的通信系统的色散进行补偿。     

八角格子色散补偿光纤

为了消除光纤通信系统中色散,采用各向异性完全匹配层和全矢量有限元方法,进行了理论分析和实验验证,设计了一种基于八角格子晶体的同轴双芯色散补偿光子晶体光纤;得到了该色散补偿光纤的传输特性如基模有效折射率、色散、损耗和非线性系数方面的数据,并分析了光纤波导色散与色散补偿光纤结构参量之间的关系。结果表明,所设计的光纤在200nm的负色散范围内,拥有负色散值(在波长为1.55m处有最低负色散值-1500 ps/(nmkm)),同时在E+S+C波段有较低的限制损耗(小于3.3dB/km);非线性效应也得到显著抑制。     

基于MEMS硅基波导的W波段大功率倍频源设计

基于自主MEMS工艺,通过在203.2 mm(8英寸)的硅晶圆上采用刻蚀、镀金、键合等工艺途径实现了硅基波导结构,设计并制作了W波段硅基波导带通滤波器和W波段硅基波导H-T合成器.测试结果表明MEMS工艺制作的硅基波导器件具有很高的一致性.以此硅基波导器件为基础,研制了W波段大功率8倍频源.经测试,该倍频源在92～96...     

硅基光子集成宽带大色散延时芯片（特邀）

集成、宽带、大色散延时的器件在微波光子滤波、真延时相控阵天线等领域有着重要的应用,可以有效地降低系统尺寸和功耗。文中提出并实现了一种基于硅基光子集成的宽带大色散延时芯片,通过采用超低损耗波导结构和侧壁法向量调制结构实现了片上集成大色散波导光栅,色散值超过250 ps/nm, 最大群延时达到2440 ps,带宽大于9.4 nm,该芯片有望用于微波光子学、高速光纤通信系统等领域。     

光子晶体光纤的色散特性分析

采用有效折射率模型分析了光子晶体光纤的色散特性，并给出了无限大空气玻璃微结构中基模的本征方程。分析结果表明光子晶体光纤具有奇异的色散特性，能在极大的波长范围内支持单模传输，在单模工作时可以具有反常波导色散。同时通过调整光子晶体光纤的结构参数(包括空气孔径和孔间距)可以移动零色散点的位置。最后讨论了大空气孔光子晶体光纤的特性及其在色散补偿中的应用。     

基于PPLN波导的全光译码器的设计与研究

随着互联网的发展,网络数据流量极速增长,全光网(AON)概念的提出有利于解决可用带宽受限、信号传输速率较低等问题。其中,全光逻辑信号处理为AON的重要组成部分。根据周期性极化铌酸锂(PPLN)波导的二阶非线性效应原理,将产生的输出信号连续送入不同的PPLN波导进行叠加处理,设计出全光2线-4线译码器的波导级联结构,通过数值计算仿真得到了波形图和眼图,分析了全光2线-4线译码器输出信号的半高全宽(FWHM)、峰值功率、延迟时间和消光比。仿真结果表明:采用PPLN波导级联的方式实现了2线-4线译码器在光域中的逻辑功能,同时保证了光信号的传输质量,为PPLN波导的全光信号处理提供了新的器件类型。     

Dispersion characteristics of nanometer-scaled silicon nitride suspended membrane waveguides

We investigate the dispersion properties of nanometer-scaled silicon nitride suspended membrane waveguides around the communication wavelength and systematically study their relationship with the key structural parameters of the waveguide. The simulation results show that a suspended membrane waveguide can realize anomalous dispersion with a relatively thinner silicon nitride thickness in the range of 400 to 600 nm, whereas, for the same membrane thickness, a conventional rib or strip silicon nitride waveguide cannot support anomalous dispersion. In particular, a waveguide with 400 nm silicon nitride thickness and deep etch depth (r=0.05) exhibits anomalous dispersion around the communication wavelength when the waveguide width ranges from 990 to 1255 nm, and the maximum dispersion is 22.56 ps/(nm·km). This specially designed anomalous dispersion silicon nitride waveguide is highly desirable for micro-resonator based optical frequency combs due to its potential to meet the phase-matching condition required for cascaded four-wave-mixing.     

Analysis of Optical Singal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory,the optical signal transmission characteristics in input/output waveguides,slab waveguides and arrayed waveguides of the arrayed waveguide grating(AWG) multi/demultiplexer are analyzed.The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed.This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.     

Analysis of Optical Signal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.     

Chip-scale optical interconnects and optical data processing using silicon photonic devices

Recent advances in the density and complexity of photonic integrated circuits have facilitated possible implementation of chip-scale optical communication systems. Chip-scale optical interconnects and optical data processing are two important functions to transmit and process signal in the optical domain. Silicon photonics offers a promising platform to enable chip-scale optical interconnects and optical data processing using silicon photonic devices. In this paper, we review our recent progress in the design, modeling, and fabrication of silicon photonic devices and their applications in chip-scale optical interconnects and optical data processing with advanced modulation formats. For chip-scale optical interconnects, we experimentally demonstrate digital signal transmissions in silicon microring and silicon vertical slot waveguide. Terabit chip-scale optical interconnect is demonstrated in the experiment. Also, we experimentally demonstrate analog signal transmissions in silicon microring and silicon photonic crystal nanocavity. For chip-scale optical data processing, we experimentally demonstrate all-optical wavelength conversion using a silicon waveguide, simultaneous polarization and wavelength demultiplexing using 2D grating coupler connected with microrings, two-mode (de)multiplexing using a tapered asymmetrical grating-assisted contra-directional coupler, and two-/three-mode (de)multiplexing using asymmetrical directional converter. In addition, we propose and simulate chip-scale optical data exchange, chip-scale high-base optical computing, and chip-scale optical coding/decoding by using nonlinear interactions in a silicon-organic hybrid slot waveguide. The obtained theoretical and experimental results of chip-scale optical interconnects and optical data processing indicate possible integration of optical communication functions on a monolithic chip.     

Si基槽型光波导的传输特性分析和传输损耗的测量

对Si基槽型(slot)光波导的传输特性进行了研究。 采用三 维时域有限差分(3D-FDTD)法研究了芯层中的光功率与波导槽型宽度及Si条带宽度之间的关 系,结果显示,槽型光波导具有很好的光功率约束效率,可以达到30%以上; 分析了光功率的变化规律及其优化,综合考虑光功率和光功率密度确定波导结构参数,实现 最佳光功率分 布,横向光功率分布沿x轴方向具有很好的约束效果,沿y轴方向呈现高斯分布;分析了底部Si薄层对光 功率的影响,100nm的底部Si薄层使得芯层的光功率下降50%,减小 底部Si薄层厚度有利于光功率约束效 率的提高;采用电子束刻写(EBL)技术和等离子刻蚀(ICP)技术制备了Si基槽型光波导,实验 研究了其传输损耗,结果显示,槽型光波导具有较低的传输损耗,达到13.5dB/cm。     

A New Formulation of Coupled Propagation Equations in Periodic Nanophotonic Waveguides for the Treatment of Kerr-Induced Nonlinearities

Nonlinear phenomena could be used to implement important signal processing functionalities in future nanophotonic integrated optical devices. In this paper, a semi-analytical model incorporating the influence of Kerr-induced nonlinearity in the propagation of an optical signal inside a periodic nanophotonic waveguide is derived. The approach consists of a system of nonlinear coupled mode propagation equations and is applicable to both single and multimode waveguides. The influence of the mode group velocity on the value of the self-phase modulation coefficient gamma is analyzed and the impact of higher order nonlinear terms is also investigated both at the middle and edge of the guided band. The model is also applied to estimate the nonlinear coupling coefficients of a photonic crystal waveguide coupler and provides an efficient method to analyze the influence of nonlinear phenomena in periodic nanophotonic waveguide devices.     

A thin-film waveguide photodetector using hydrogenated amorphoussilicon

Metal-silicon-metal cladding layers on dielectric waveguides exhibit coupling and absorption characteristics that make them useful as photodetectors for integrated optical applications. Multilayer computer-modeling techniques were applied to waveguide photodetectors in order to investigate field and power distributions, as well as the attenuation and phase response in the guiding region. A waveguide photodetector based on amorphous silicon was fabricated and demonstrated     

Dispersive properties of Kerr-like nonlinear optical structures

The control of the group velocity dispersion (GVD) is of great concern in the design of photonic devices and may be obtained controlling the waveguide components of the GVD. Under high optical field intensity the dispersive properties of the waveguides are different from the linear state and a nonlinear model of the guide must be considered. A rib waveguide has been investigated and a finite element procedure together with a second-order perturbation technique have been used to calculate the waveguide dispersion and to compare the results in linear and nonlinear states