聚合物定向耦合电光开关的模拟和优化

阐述了定向耦合电光开关的基本结构及工作原理,利用耦合模理论和电光调制理论,在1 550 nm波长下,对器件的结构参量进行了优化,并对其传输光谱、开关电压、插入损耗、串扰等特性进行了分析.模拟过程中,考虑了因金属电极和聚合物材料引起的模式损耗.器件的结构参量优化值为：波导芯截面尺寸为1.7×1.7 μm2,波导芯与电极间的限制层厚度为1.5 μm、电极厚度为0.15 μm,波导间的耦合间距为2.0 μm,相应的耦合长度为2 926 μm.模拟结果表明,本文所设计的器件在开关转换电压0和17.4 V下,在1 534到1 565 nm的波长范围内,器件的插入损耗小于0.16 dB,串扰小于－20 dB,耦合区在2 734~3 120 μm范围内,器件的插入损耗小于0.22 dB,串扰小于－20 dB.     

聚合物2×2定向耦合型电光开关

设计并制作了一种聚合物2×2定向耦合型电光开关.针对溶胶-凝胶法合成的有机/无机杂化电光材料膜厚较薄的情况,采用一种加载条形波导结构,利用掺有环氧丙脂的聚甲基丙烯酸甲脂-甲基丙烯酸缩水甘油脂作为引导层,在电光薄膜上构成定向耦合器,通过紫外光刻、反应离子刻蚀、电晕极化等工艺,制备了聚合物定向耦合型电光开关,并采用共面波导行波电极以电推挽方式工作.经测试,其器件损耗约为16 dB,开关电压9 V.     

聚合物定向耦合电光开关的高频响应特性分析

应用耦合模理论、电光调制理论、保角变换法和镜像法,给出了分析聚合物定向耦合电光歼关高频响应特性的功率传输矩阵新方法,导出了输出功率、上升时间、下降时间、开关时间及截止开关频率的表达式.为了获得较低的传输损耗、较好的阻抗匹配、较小的开关电压以及较高的截止频率,优化设计了器件的波导结构和电极结构.模拟结果表明,所设计器件的开关电压为1.457 V,耦合长度为4.374 mm,开关时间为32.8 ps,截止开关频率为114.7 GHz.与点匹配法的计算结果和实验结果的对比表明,该理论分析方法具有较高的精度.     

聚合物串联耦合双环电光开关的优化

利用耦合模理论、电光调制理论和微环谐振理论,提出一个聚合物串联耦合双环电光开关器件模型,在1.55 μm谐振波长下对该器件进行了模拟和优化.结果为：微环波导芯截面尺寸为1.6×1.6 μm2,波导芯与电极间的限制层厚度为1.6 μm,电极厚度为0.15 μm,微环半径为15.2 μm,微环与信道间的耦合间距为0.14 μm,微环与微环间的耦合间距为0.6 μm,输出光谱的3 dB带宽约为0.06 nm,开关电压约为6 V左右,插入损耗约为2.2 dB,串扰约为－20 dB.所设计的双环电光开关较单环型电光开关不仅输出光谱更加平坦陡峭,非谐振光更弱,而且开关电压更低.     

聚合物微环谐振器电光开关阵列的优化与模拟

利用耦合模理论、电光调制理论和微环谐振理论,提出了一个聚合物微环谐振器电光开关阵列的模型.该器件由N-1个微环和N条平行信道构成,在微环上施加不同方式的驱动电压,可以实现N条信道的开关功能.以7微环8信道结构为例,在1550 nm谐振波长下对该器件进行了优化和模拟.结果表明,微环波导芯的截面尺寸为1.7μm×1.7μm,波导芯与电极间的缓冲层厚度为2.5 μm,电极厚度为0.2μm,微环半径为13.76 μm,微环与信道间的耦合间距为0.14μm,输出光谱的3 dB带宽约为0.05 nm,开关电压约为8.1 V左右,插入损耗约为0.23～4.6 dB,串扰小于-20 dB.     

1×N信道聚合物微环谐振器电光开关阵列的开关特性

利用耦合模理论、电光调制理论和微环谐振理论,提出了一个完善合理的聚合物微环谐振器电光开关阵列模型.该器件由1条水平信道、N条竖直信道和N个微环构成,在微环上施加不同方式的驱动电压,可以实现N+1条信道的开关功能.以1×8信道结构为例,在1 550 nm谐振波长下对该器件进行了优化设计和模拟分析.其结果是:微环波导芯的截面尺寸为1.7×1.7 μm2,波导芯与电极间的缓冲层厚度为2.5 μm,电极厚度为0.2 μm,微环半径为13.76 μm,微环与信道间的耦合间距为0.14 μm,输出光谱的3 dB带宽约为0.05 nm,开关电压约为12.6 V,插入损耗约为0.67～1.26 dB,串扰小于-20 dB,开关时间约为11.35 ps.     

两节推挽极化波导Y型耦合器电光开关特性分析（英文）

针对两节独立反相集总电极聚合物Y型耦合器电光开关响应速度慢的问题,通过对该器件两节电光区的波导进行推挽极化,设计了一种无偏置行波电极高速电光开关.为了获得低的驱动电压、良好的阻抗匹配和光波与微波间较小的折射率失配,对电极参数做了设计和优化.通过对施加的方波开关信号做傅里叶变换并结合行波传输线理论,给出了一种用于建模和表征器件高频响应的解析分析法.对该器件的数值计算结果表明,在1 550nm中心工作波长下,其3dB状态电压为0 V,开关电压为2.68V,上分支状态电压和下分支状态电压分别为-1.34V和+1.34V,器件的插入损耗和串扰分别小于3.55和-30dB,10%~90%上升时间和下降时间均为3.90ps,截止开关频率可达128.2GHz.     

一种定向耦合器型高聚物光开关设计

本文提出了一种基于定向耦合器型的高分子聚合物波导光开关设计,其突出特点是极低的波长相关性和耦合区几何尺寸敏感度,可采用橡胶成型工艺(Rubber Molding Process)实现高聚物波导在硅基底上的快速转印成型.利用BPM方法进行了器件的波导结构设计及性能模拟,插入损耗为0.4-0.6 dB,串扰<-32 dB,偏振相关损耗约为0.08 dB,电光系数r33＝14 pm/V时,器件的开关电压为42 V.     

一种带有U形波导的交叉信道单微环电光开关

本文利用耦合模理论,电光调制理论和传输矩阵法,提出了一个带有U形波导的交叉信道单微环电光开关的器件模型,并在谐振波长为1561 nm的情况下对该器件进行了仿真计算.结果表明,该电光开关的开关电压约为400 V,串扰小于-30 dB,插入损耗小于4 dB,开关时间仅为5.4 ps,其中微环上的上升和下降时间仅为0.32 ps.此外,该电光开关由单刀双掷开关控制,通过在微环和U形波导上加载驱动电压可实现三种开关状态,不仅可以实现光信号在两条输出信道的选择,还可以使两条信道同时有光信号输出.     

1×|N 信道聚合物微环谐振器电光开关阵列的开关特性

利用耦合模理论、电光调制理论和微环谐振理论,提出了一个完善合理的聚合物微环谐振器电光开关阵列模型.该器件由1条水平信道、N条竖直信道和N个微环构成,在微环上施加不同方式的驱动电压,可以实现N＋1条信道的开关功能.以1×8信道结构为例,在1 550 nm谐振波长下对该器件进行了优化设计和模拟分析.其结果是：微环波导芯的截面尺寸为1.7×1.7 μm2,波导芯与电极间的缓冲层厚度为2.5 μm,电极厚度为0.2 μm,微环半径为13.76 μm,微环与信道间的耦合间距为0.14 μm,输出光谱的3 dB带宽约为0.05 nm,开关电压约为12.6 V,插入损耗约为0.67~1.26 dB,串扰小于－20 dB,开关时间约为11.35 ps.     

Design of a polymer directional coupler electro-optic switch using two-section reversed electrodes

By using the coupled mode theory, electro-optic modulation theory, conformal transforming method and image method, the structure is designed, the parameters are optimized, and the characteristics are analyzed for a polymer directional coupler electro-optic switch with two-section reversed electrodes. Simulation shows that the designed device exhibits excellent switching functions. Under the operation wavelength of 1550 nm, the electro-optic coupling region length is 4751 μm, the cross-state and bar-state voltages are about 1.22 and 2.65 V, and the insertion loss and crosstalk are less than 2.21 and −30 dB, respectively. By slightly adjusting the state voltages, the blight of the fabrication errors on the switching characteristics can be easily eliminated. The calculation results of the presented technique are in good agreement with those of the beam propagation method (BPM).     

Analysis on skin-effect of a polymer shielded push–pull directional coupler electro-optic switch

By using the extended point-matching method, coupled mode theory, and electro-optic modulation theory, design and optimization are carried out for a polymer shielded push–pull directional coupler electro-optic switch. A novel technique and the relative formulas are presented for analyzing the influences of the skin-effect on the microwave characteristic parameters and the switching performances. Simulation results show that the voltages of the cross- and bar-states are 0 and ±2.93 V, respectively, and the coupling length is 4.139 mm. Considering the influences of the skin-effect, the cutoff switching frequency is 172 GHz, the insertion loss is in the range of 1.920–1.975 dB, the crosstalk is less than ?20 dB, and the switching time is 31.18–31.40 ps within the range of the switching frequency from 0.72 to 172 GHz. The designed switch exhibits superior characteristics including good impedance match, low switching voltage, and high cutoff switching frequency.     

Analysis of response characteristics for polymer directional coupler electro-optic switches

By using the coupled mode theory, electro-optic modulation theory, conformal transforming method, image method and the proposed transfer matrix technique, novel expressions for the both cases of the low switching frequency and the ultra-high switching frequency are presented for analyzing the transmission powers, rise time, fall time, switching time and switching frequency of the polymer directional coupler electro-optic switches. Simulation results of an application based on the technique show that, the switching voltage and coupling length are about 1.457 V and 4.374 mm, respectively, and the switching time and cutoff switching frequency are about 32.8 ps and 114.7 GHz, respectively, for the designed switch.     

Simulation and optimization of a polymer directional coupler electro-optic switch with push-pull electrodes

Structural model and design technique are proposed for a polymer directional coupler electro-optic switch with rib waveguides and push-pull electrodes, of which the electric field distribution is analyzed by the conformal transforming method and image method. In order to get the minimum mode loss and the minimum switching voltage, the parameters of the waveguide and electrode are optimized, such as the core with, core thickness, buffer layer between the core and the electrode, coupling gap between the waveguides, electrode thickness, electrode width and electrode gap. Switching Characteristics are analyzed, which include the output power, insertion loss, and crosstalk. To realize normal switching function, the fabrication error, spectrum shift, and coupling loss between a single mode fiber (SMF) and the waveguide are discussed. Simulation results show that the coupling length is 3082 μm, push-pull switching voltage is 2.14 V, insertion loss is less than 1.17 dB, and crosstalk is less than −30 dB for the designed device.     

Fourier analysis of a polymer directional coupler electro-optic switch with two-section cosine-transitive CPWG electrodes: A new theoretical view

By using two-section cosine-transitive coplanar waveguide grounded (CPWG) electrodes, a polymer directional coupler (DC) electro-optic (EO) switch is optimally designed with both relaxed fabrication tolerance under cross-state and high switching speed over 100 GHz. As a new theoretical view, based on Fourier transformation, a Fourier analysis technique and related formulas are presented with respect to the time- and frequency-domain responses under high-speed modulating and switching operations. Under 1550 nm, the bar- and cross-state voltages are 0 and 2.669 V, respectively, for the switch with a total length of 8378 μm. The insertion loss and crosstalk are less than 3.887 and ? 30 dB, respectively. The 3-dB modulating bandwidth and cutoff switching frequency are about 110 and 131.6 GHz, respectively, and the 10–90% rise time and fall time are both about 3.80 ps. Owning to this configuration, its cutoff switching frequency is enhanced to 9 times of that of our previously reported EO switch with two-section separated reversed electrodes, which expands the ultra-high speed and large capacity applications for such switches. The proposed Fourier analysis method can also be adopted to evaluate the responses under the operation of any other form driving signals with Fourier transformation.     

Investigation on push-pull polymer Mach-Zehnder interferometer electro-optic switches using improved 3-D mode propagation analysis method

By introducing normalized mode excitation coefficient and total mode excitation coefficient, we improve the 3-D mode propagation analysis (MPA) method for convenient design and analysis of multimode interference (MMI) coupler. With the improved 3-D MPA method and point-matching method, we present a novel formulation technique to analyze the low- and high-frequency characteristics for the impedance-matched polymer Mach-Zehnder interferometer electro-optic (EO) switch based on MMI couplers. As an application, under 1550 nm, optimization and simulation performed for the designed device reveal low driving voltage of 1.375 V with short EO region length of 5 mm. The insertion loss and extinction ratio are less than 3.75 dB and more than 42 dB, respectively. The microwave characteristic impedance is about 49.6 Ω, and due to the less mismatch between lightwave velocity and microwave velocity, the estimated cutoff switching frequency is up to 263 GHz with the 10–90% rise time and fall time about 1.90 ps under the operation of step-style square-wave switching signal. This theoretical cutoff switching frequency is almost 1.53 times of that of our previous reported shielded EO switch with similar design technique.     

Polymeric Multimode Interference Mach–Zehnder Interferometer Electro-Optic Switch Using Embedded Coplanar Waveguide Electrode: Theory,Design, and Analysis

Abstract

The self-imaging theory is improved for designing a polymer multimode interference Mach–Zehnder interferometer electro-optic switch. The electro-optic overlap factor is enhanced from 0.6510 to 0.9658 through adopting an embedded coplanar waveguide electrode. Considering the mode dispersion effect, formulations of time-domain response are derived, and switching characteristics are analyzed. The total device length is about 7.175 mm, the switching voltage is 2.622 V, and the switching time is 29.90 ps. The lightwave 3-dB bandwidth is 20 nm, the insertion loss is less than 2.70 dB, and the crosstalk under cross and bar states are less than ?55 dB and ?45 dB, respectively.