微波波段带通光调制器的优化设计

本文对具有极性反转电极结构的行波皮导电光调制器的调制特性进行了理论分析，对共平面波导电极和非对称微带电极用于极性反转电极结构下的有关特征参量进行了数值计算，对使用这两种电极制成的调制器，我们用带宽－长度积、电压－长度积和带宽－电压比这三个品质因子对其性质进行了比较，本文还给出了调制器的设计实例，对结果的分析讨论表明，非对称微带电极用于极性反转电极结构对在高频波段实现低动功率光调制是十分有效的。     

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.     

2 bit光波导模数转换器的模拟设计

采用有限差分束传输法对2bit集成光学模数(AD)转换器的波导结构进行了模拟分析与设计．采用保角变换方法对MZ调制器的电极参数进行分析与设计,得到优化参数为：带宽Δf=1．3GHz,半波电压Vπ=4V,传输损耗为0．0172dB/cm。     

微波部件、毫米波部件

0619870一种大功率宽频带低损耗定向耦合器的设计与实现[刊,中]／田丰／／电子科技．-2006,(4)．-47-50(D)根据传输线变压器串并联同时耦合的原理,设计了一种13dB铁氧体定向耦合器,该定向耦合器是用漆包线绕在射频铁氧体磁芯上做成。具有尺寸小、结构简单和频带宽等优点,工作范围在100～400MHz。对其参数进行了理论计算和测量,满足设计要求。经过实际应用,验证了设计方法的可行性。参3     

Fabry-Perot型GaAs-GaAIAS DH激光放大器的增益和频率带宽

本文报导了用实验方法研究Fabry-Perot型GaAs-GaAlAs DH半导体激光放大器的结果。在共振放大条件下测量了总增益G_C及其随注入电流的变化,并通过G_C随入射光频率γ的变化测得频率带宽⊿v_(1/2)。用Hakki-Paoli的方法测量了光放大器的增益系数随注入电流的变化,求得单程增益G_S随注入电流的变化,利用G_S计算了G_C随注入电流的变化及频率带宽⊿v_(1/2)。计算结果和实验值符合较好。     

氯化亚汞声光器件三层换能器的优化设计

提出用环氧树脂聚合物作为缓冲层，设计氯化亚汞声光器件的换能器。从器件的布喇格带宽和工艺条件出发，优化设计了三层（含顶电极，缓冲层，底电极）结构的换能器，计算了以不同金属材料为电极时，其三层的各自厚度，并确保了换能器的倍频程带宽。     

Nd:NaY(WO4)2晶体的热焦距及最佳泵浦位置

用光纤耦合的半导体激光器(LD)泵浦Nd^3-：NaY(WO1)2(Nd：NYW)晶体,采用非稳腔法测量了晶体在泵浦功率3．5～6．5w范围内的热焦距,并与理论计算结果进行了比较;同时,测量了不同泵浦功率下的最佳泵浦位置,理论分析计算与实验结果相符合,并对实验现象作出了合理的解释。     

基于时域法的单条形InP/InGaAsP-EAM调制器的行波电极的仿真与实验研究

行波电极(Traveling wave electrode,TW),是目前广泛采用的一种电极结构,可缩短光载波与调制信号的互作用长度,可有效避免分布电容(Contribution capacity,CR)对调制带宽的限制.基于时域法设计、分析了InP/InGaAsP-EAM调制器行波电极,并与实际制作的EAM的行波型TW进行了特征阻抗Zc、损耗系数α对比,结果表明用时域法设计、计算的TW的特征阻抗、损耗系数与实测的结果符合的较好,特征阻抗约为45Ω,在0～20 GHz的频率范围,损耗系数α小于4 dB/mm.     

CMOS单片光接收机的带宽设计

设计了一个由调节型级联跨阻抗放大器(TIA)和双光电二极管(DPD)构成的光电集成接收机.给出了DPD小信号电路模型和单片集成光接收机的带宽设计方法,给出限制DPD和光接收机带宽的重要因素,分析和模拟了这个光电集成接收机的带宽,用低成本的0.6μm CMOS工艺设计出1.71GHz带宽和49dB跨阻增益的接收机,并给出测试结果.     

微带短路岔线型超宽带滤波器单壳的分析与设计

提出了一种适合超宽带滤波器没计的微带短路岔线(sbert-circuited spurline)的组合结构,给出了该组合结构幅频、相频响应的计算方法.该结构带宽能够达到超宽带的要求,并有易于加工、伸展面积小等优点.根据理论分析,设计、仿真并制作了一个微带短路岔线滤波器单元,分析和测量结果吻合.     

High-speed shielded velocity-matched Ti:LiNbO3 opticalmodulator

A shielded velocity-matched Ti:LiNbO₃ optical modulator is investigated, focusing on the characteristics of the traveling-wave (TW) electrode and the optical waveguide. The optical waveguide is analyzed and its parameters are determined using the newly developed modified-step-segment method (MSSM). The TW electrode is analyzed using the second-order triangular element quasi-TEM finite element method (FEM). By taking the thickness of the coplanar waveguide (CPW) traveling-wave (TW) electrode into consideration, it is confirmed that there is an optimum overlaid layer thickness for a given electrode thickness. It is also shown that very wide modulation bandwidth can be attained by using the optimum CPW TW electrode thickness and overlaid layer thickness     

GaAs traveling-wave optical modulator using a modulated coplanar strip electrode with periodic cross-tie overlay

This paper proposes and analyzes a GaAs traveling-wave optical modulator which uses a modulated coplanar strip electrode with periodic cross-tie overlay. This slow-wave structure can be designed to satisfy phase velocity and impedance matching conditions simultaneously. The dominant conductor loss in the slow-wave structure is reduced using the modulated coplanar strip electrode. The calculated 3-dB modulation bandwidth (100 GHz) is much wider than the bandwidth limit (30 GHz) of conventional electrode structures that are limited by phase velocity mismatch.     

Mach-Zehnder Type Annealed Proton Exchange Waveguide and Coplanar Waveguide Modulation Electrode LiNbO3 Intensity Modulator

The characteristics of a conventional LiNbO3 intensity modulator made up of a Mach-Zehnder （MZ） type annealed proton exchange（APE） waveguide and coplanar waveguide（CPW） modulation electrode are presented. The APE waveguide characteristics and their relations with process parameters are analyzed. At the same time, the electrical characteristics of modulation electrode, such as modulation voltage, microwave effective index associated with modulation bandwidth, characteristics impedance, are also investigated in detail.     

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.     

Electrode optimization for high-speed traveling-wave integratedoptic modulators

Different electrode configurations for LiNbO₃-based Mach-Zehnder traveling-wave electrooptic modulators are analyzed. It is found that the Z-cut coplanar waveguide (CPW) configuration provides the best compromise between the characteristic impedance, the half-wave voltage, and the driving power. To increase the bandwidth and simultaneously reduce the half-wave voltage, an optimum design of multisection phase reversal electrode is proposed. To verify the theoretical predictions experimentally, two modulators, both using the Z-cut LiNbO₃ CPW configuration, were fabricated and characterized, one with an optimized five-section phase reversal electrode and the other with a conventional single-section electrode. By comparing the performances of these two devices, it is confirmed that significant improvements on the bandwidth to half-wave voltage ratio and the flatness of the frequency response can indeed be obtained from using an optimized multisection phase reversal electrode     

A wide-band Ti:LiNbO3 optical modulator with aconventional coplanar waveguide type electrode

The design and fabrication parameters needed to obtain a low-loss coplanar waveguide structure were determined. A large optical bandwidth (more than 23 GHz) and low driving voltage (5 V) Ti:LiNbO₃ Mach-Zehnder interferometer type optical modulator at a wavelength of 1.52 μm, using a conventional and thick coplanar waveguide type electrode structure     

The transverse electrooptic modulator (TEOM): fabrication,properties, and applications in the assessment of waveguide electroopticcharacteristics

The fabrication of a novel electrooptic modulator with a transverse electrode geometry, formed by parallel electrodes on opposite faces of a thinned lithium niobate substrate straddling a strip waveguide, is reported. The device, referred to as a transverse electrooptic modulator (TEOM), has several advantages over standard electrooptic waveguide modulators using a coplanar electrode geometry. It is shown that it is possible to achieve a 30% reduction in the operating voltage for a given electrode spacing and a substantial reduction in the figure of merit, the power required per unit bandwidth, for electrooptic modulators with either lumped or traveling wave electrode structures. Moreover, a more accurate estimate of the electrooptic coefficients is possible than with modulators using strip waveguides and coplanar electrodes     

Design of an ultra wide-band printed monopole antenna using FDTD and genetic algorithm

This letter presents an ultra wide-band (UWB) antenna with a printed monopole structure fed by a coplanar waveguide (CPW) line. The antenna is analyzed by using the finite-difference time-domain (FDTD) method and genetic algorithm (GA) to achieve an ultra wide bandwidth characteristic. The measured frequency response shows an impedance bandwidth of 7.25GHz or 104.7% over 3.3 to 10.55GHz for VSWR less than 2.     

一种可用于体域网的小型化超宽带天线设计

基于FR4环氧板,设计了一种可用于体域网的非对称共面波导馈电的超宽带天线。该天线由Y型贴片、梯形地板和三叉戟共面馈线组成。Y型贴片、圆形贴片、三角形贴片实现4~5 GHz的中低频处带宽小于-10 d B的效果,梯形地板和三叉戟共面馈线实现7~14 GHz的高频处带宽小于-10 d B的效果。该天线采用非对称共面波导的馈电方式,具有良好的共面性与高度的集成性,使得天线的总体尺寸更小,辐射贴片的面积为22 mm×21 mm。与以往的小型化超宽带天线相比,该天线具有尺寸更小、带宽更宽的优势。经网络矢量分析仪测试结果表明,该天线在2. 14~11. 32 GHz的超宽带频段内回波损耗小于-10 d B(相对带宽为136. 4%),可适用于2. 4/5. 2/5. 8 GHz无线局域网、3. 5/5. 5 GHz WiMAX、LTE频段38和LTE频段40。同时,该天线距离人体大于5 mm时的比吸收率(SAR)小于2 W/kg,满足国际标准。     

应用于40Gb／s电吸收调制器的Al2O3高速热沉研究

设计制作了面向40Gb/s电吸收调制器(EAM)的高速微波过渡热沉,并进行了EAM管芯级封装测试的验证.这种基于氧化铝(A l2O3)的热沉采用共面波导(CPW)传输线以实现低损耗微波传送,以及Ta2N薄膜电阻用于EAM的阻抗匹配.采用Ti/Cu/N i/Au金属材料作为CPW传输线电极材料,从而保证CPW传输线与Ta2N电阻材料之间良好的电接触,使热沉的典型反射系数在0~40 GHz范围内均达到优于-21 dB的水平.作为验证,采用该种热沉用于高速EAM的管芯级封装,测试得到小信号调制响应带宽超过40 GHz.