行波型LiNbO3电光调制器的电极优化设计

利用扩展点匹配方法对厚电极厚缓冲层的共面波导电光调制器的结构和性能参数进行了分析和研究,通过仿真选择合适的电极厚度和缓冲层厚度,所得的特性阻抗和有效折射率与采用保角变换法得到的结果吻合,优化了调制器性能,实现了宽带调制.这一分析方法简便快捷,能够处理电极有一定厚度的多层光波导调制器结构.     

用数值分析方法设计波导电光调制器

本文描述了波导电光调制器傅里叶级数数值分析设计的新方法，利用计算机对波导电光调制器进行傅里叶级数数值计算，得到波导电光调制器的电级的电场分布、器件的特性阻抗和有效介电常数，在此基础上设计出带宽可达７．４ＧＨｚ／ｃｍ和特性阻抗秋５０Ω的波导电光调制器。     

波导光电器件的微波有效折射率——器件微波折射率

以波导电光调制器芯片结构为例 ,利用点匹配法计算调制器芯片的电场分布 ,从而计算调制器电极的微波有效折射率 ,由此提出了器件折射率的概念。进一步证明了当光电信号互相匹配时调制带宽可达 10 0GHz。     

一种宽带低啁啾z切Ti∶LiNbO3调制器

对正常型和反转极化型LiNbO3波导在任意方向加电场,由线性电光效应引起的折射率的变化做了计算分析,结果发现只有在z方向加电场,LiNbO3两波导臂折射率的变化才是完全相反的.实验验证得到了同样结论.提出一种利用反转技术、厚电极制作和脊型结构的新型宽带低啁啾的LiNbO3调制器.计算结果表明,在实现光波和微波速度匹配情况下,当器件的微波损耗系数为0.15 dB/(cm·√GHz),以及正常型和反转极化型LiNbO3波导长度相等时,其频率啁啾参数非常小,40 GHz时约为0.1.     

脊波导结构LiNbO3电光调制器研究与改进

采用有限元软件Ansys、运用有限元法,对脊波导结构铌酸锂电光调制器进行了优化设计。通过将传统结构与脊波导的比较分析,提出采用聚四氟乙烯部分取代缓冲层中的二氧化硅的结构,能更好的实现微波等效折射率的降低以达到与光波折射率的匹配,同时能保持更大的特性阻抗以实现阻抗匹配,从而更好的提高器件性能。     

X切LiNbO3脊形结构集成电光M-Z型调制器

采用X切LiNbO3 基片 ,设计并研制了脊形结构集成电光Mach Zehnder(M Z)波导调制器 ,实验研制过程包含关键的LiNbO3 基片湿腐蚀刻槽技术和大厚度电极制作技术。研究结果表明 ,脊形结构调制器与传统的平面结构调制器相比 ,在大幅度提高调制带宽方面 ,有着明显的优越性     

脊波导结构LiNbO3调制器的分析与设计

本文利用保角变换法对脊波导结构调制器进行了分析,特别针对在制做脊波导时的非理想矩形的情况,对它造成的偏差进行了计算,在此基础上得出了脊型共面波导结构调制器的等效折射率,特性阻抗,调制带宽和驱动电压等特性。在速度匹配,阻抗匹配,半波电压以及制做的困难程度等折中考虑下对调制器的各项参数进行了优化。结果表明了这新型结构在保持较大特性阻抗的同时,有效的降低等效折射率,大大地提高了调制带宽,迎合了更高速光纤通信的要求。     

脊波导结构LiNbO3调制器的分析与设计

本文利用保角变换法对脊波导结构调制器进行了分析,特别针对在制做脊波导时的非理想矩形的情况,对它造成的偏差进行了计算,在此基础上得出了脊型共面波导结构调制器的等效折射率,特性阻抗,调制带宽和驱动电压等特性。在速度匹配,阻抗匹配,半波电压以及制做的困难程度等折中考虑下对调制器的各项参数进行了优化。结果表明了这新型结构在保持较大特性阻抗的同时,有效的降低等效折射率,大大地提高了调制带宽,迎合了更高速光纤通信的要求。     

硅单模脊形光波导的三维模拟及实测结果

对当前硅光集成技术的热点、制备大断面低传播损耗单模脊形光波导进行了三维理论模拟设计。脊的上覆盖层是空气（大折射率台阶，非对称情况）或纯硅层（对称情况），均能得到符合实际的模拟结果。改变脊形光波导的高宽几何尺寸或折射率分布值，模拟结果呈现单模、双模或更高阶模的电场分布及光强分布。用相应条件指导硅脊形光波导的实际制备，实测结果表明模拟结果是准确的。     

PMMA脊形光波导的设计与场分析

利用有效折射率法（EIM）理论设计了有机聚合物脊形光波导结构,并分析光波导中传输的模式场,确定出光波导结构的适宜尺寸范围。光波导结构中分别选用PMMA（聚甲基丙烯酸甲酯）与PDMS（聚二甲基硅氧烷）作为波导层与包层的材料,用光漂白法来实现脊形波导结构。首先利用EIM法分析脊形波导区的宽度与高度之间的关系对归一化色散曲线的影响,以及波导层与包层的折射率匹配的影响,然后又通过分析波导区传输的基模场来讨论传输的损耗问题。研究发现波导结构的脊宽与脊高之比w／d越大,其有效折射率neff越大,而此结构尺寸又需约束在一定范围内,否则将造成很大的传输损耗。     

Design and analysis of coplanar waveguide optical modulator using finite element method

An analysis is given on the finite element method (FEM) for calculating the various parameters of optical modulators and a computer program is written to solve the finite element equation. Based on this method, a Mach-Zehnder type electro-optic modulator with coplanar waveguide (CPW) electrode is designed and fabricated. When compared with the Fourier series method, small differences on the 3-dB bandwidth, characteristic impedance and half-wave voltage, etc. are obtained.     

Hybrid Electrodes Used in Polymer Electro-Optic Modulator with Ultra-Broadband

Hybrid electrode combined coplanar waveguide (CPW) and microstrip lines in ultra-broadband electro-optic modulators. The characteristics of the modulators with hybrid electrode is like that of the modulator with the microstrip lines, in which the microstrip electrode is loaded above only one arm of Mach-Zehnder (M-Z) optical waveguide, besides the problem of microstrip line to coaxial transition and corona polarization in polymer modulators have been best solved at the same time. By using finite element method (FEM), the characteristic parameters such as half-wave voltage, modulation bandwidth characteristic impedance, effective microwave refractive index of polymer modulators with microstrip line and hybrid electrode are analysed and compared in this paper. The results present that velocity match, impendence match and lower microwave propagating loss is easily realized in modulators with hybrid electrode.     

Microwave characteristics of high-speed traveling-wave electroopticmodulators on III-V semiconductors

Microwave characteristics of III-V semiconductor traveling wave electrooptic modulators were studied rigorously by using the method of lines. This approach makes it possible to construct a complete computer model of double-rib, multilayer strip waveguide modulators which are out of reach of the classical methods. Both p-i-n junction and Schottky-barrier junction controlled devices have been investigated. The fringing microwave field has been found to play an important role in improving the modulator bandwidth. For the first time, a nonperfect electrode of finite thickness has been modeled. The method of lines algorithm has proved to be a valuable CAD tool for design and optimization of high-speed modulators     

Ultra-Broad-Band LiNbO3 Electro-Optic Modulators with Novel Complex Electrode

The characteristics of Z- cut LiNbO3 optical modulators with novel complex electrode are discussed by using the finite element method (FEM) and studied experimentally in this paper. The travelling wave electrode consists of upper and lower parts. It can easily realize phase velocity matching between microwave and optical wave and drastically reduce microwave electrode loss. An electrooptic modulator with larger than 100 GHz bandwidth and half wave voltage 6 V is designed, fabricated and measured. Vπ is 5.1 V and the attenuation coefficient a0 is 0.3 dB/(cm· GHz1/2 ). The experimental results show that the modulator has great potentiality for expanding bandwidth.     

A finite element method (FEM) analysis of a shielded velocity-matched Ti:LiNbO/sub 3/ optical modulator

Shielded velocity-matched Ti:LiNbO/sub 3/ Mach-Zehnder optical modulators are analyzed based on the second-order triangular-element quasi-transverse-electromagnetic finite element method. The relationship between the traveling-wave electrode thickness and the optimum overlaid layer thickness is numerically investigated. The modulation bandwidth of the shielded velocity-matched optical modulator is greatly improved by incorporating the traveling-wave electrode thickness into the design of the optimum overlaid layer thickness in the 1.5 mu m wavelength region.<>     

高速InP基半导体电光调制器行波电极结构研究

对PIN型和NIN型两种InP基Mach-Zehnder电光调制器的电极结构进行了数值仿真研究,从而确定出适于这两种电光调制器的行波电极结构。仿真结果表明,NIN型电光调制器可采用简单的单臂类微带电极,而PIN型电光调制器需采用周期容性负载电极,以达到良好的阻抗匹配特性和传输特性。进一步地,提出了将串联推挽式行波电极结构应用于PIN型电光调制器,可以简化制作工艺并获得良好的微波特性。     

新型行波电极超宽带LiNbO_3电光调制器的优化设计

采用有限元法和增量电感公式对一种新型电极结构的电光调制器进行了理论分析和设计.计算中对损耗系数进行了修正.计算结果表明这种结构可以灵活地实现相速匹配和有效降低电极损耗.是一种具有超宽带潜力的调制器.用带宽和驱动功率的比值作为衡量调制器特性优劣的标准.得到了这种电极结构的一些优化尺寸.并从中发现适当增大电极间隙有利于提高器件性能.利用优化结果.给出了一带宽为100GHz.半波电压为6V的调制器设计例子.     

Modeling and optimization of low chirp LiNbO/sub 3/ Mach-Zehnder modulators with an inverted ferroelectric domain section

Domain inversion under coplanar waveguide electrodes is proposed to improve the frequency-chirping behavior of Z-cut LiNbO/sub 3/ Mach-Zehnder modulators. This is achieved by introducing a phase reversal electrode section in tandem with inverted ferroelectric domains. The method opens the way to broad-band single-drive modulators with predetermined chirp parameter. The experimental results obtained at 10 Gb/s confirm the possibility of lowering the chirp parameter of a Z-cut modulator, while keeping a halfwave voltage lower than 5 V.     

聚合物电光波导调制器中微带电极的几何参数对重叠积分的影响

本文对有机聚合物导调制器的重叠积分进行了详细计算，着重讨论了器件的几何参数对重叠积分的影响。     

Optically absorbing metallization

An electrode metallization is demonstrated that absorbs nearly all light incident upon it at specified wavelengths. This electrode may see application in reflective displays and spatial light modulators where stray light reflected off circuit metallization is deleterious. Reflection suppression of −35 dB is shown in a highly conductive metallization.