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设计了一种缺陷模迁移光子晶体微腔全光开关. 两条二维三角晶格空气孔光子晶体波导由一个光子晶体微腔连接, 在微腔的点缺陷中填充掺有少量偶氮聚合物的苯乙炔类液晶. 通过调节控制光的偏振态, 使偶氮聚合物发生顺-反异构化反应, 带动液晶分子重新取向, 从而改变光子晶体微腔的谐振波长, 进而实现光的通过与截止. 运用时域有限差分法和平面波展开法分析 了二维光控液晶光子晶体微腔全光开关的光学特性. 数值计算结果表明: 对于1.55 μ通信波段通过外界偏振光控制所填充的向列相液晶 的折射率可以实现对光波的导通与截止. 分析结果显示, 此开关具有阈值低, 消光比较大, 体积小等优点.
关键词:
二维光子晶体微腔
波导
时域有限差分(FDTD)
液晶 相似文献
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The absorption spectra characters of the (Cr,Yb):YAG,Cr:YAG and Yb:YAG crystals are reported. In the absorption spectra of the (Cr,Yb): YAG crystal,there are two absorption bands at 937 nm and 968 nm respectively,which are suitable for InGaAs diode laser pumping;and there is an absorption band of Cr4+ near 1030 nm,which is suitable for passive Q switch laser output at 1.03 μm. This Cr-Yb-codoped crystal may be a potential material for compact,diode laser pumped passive Q-switched solid-state laser with efficient,high-stable. 相似文献
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1lntroductionThsaturableabsotherswhichhavebeensucceSSfullyusedforpassiveQswitched1asersincludedye['],Lffi:F2colDcenterCrytals['],Cr -doPedcrysds['~'],etc.Amngthem,Cr -doPedCryStalsdevtheedinrecentyearssuchasCr :YAG,Cr :GSGG,andCr :WeSnyandsoon,havetheadVanageSofgoodphoto-chedcalandthermalstabillty,largabsorptbocross-section,besaturableintensityandhighdaInaethreshod.Inaddition,Cr canbedoPedintOgainmediumtoformselfQ-switchedl..,['J.Cr -dopedcrystalsbecomethemostprotalsingsatIJrable… 相似文献
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Crosstalk is one of the most important factors affecting the image quality of polarization switching three-dimensional (3D) projectors. The variation in the phase difference of a polarization switch owing to dispersion degrades crosstalk performance. We propose a novel multistage circular polarization switch comprising liquid crystal devices using a ferroelectric liquid crystal (FLC) in-plane fast switch and a thick nematic liquid crystal (NLC) retarder. In this paper, we present a proof-of-concept model of a 3D laser pico projector using a scanning MEMS head in combination with the polarization switch. We also evaluate the crosstalk and 3D performance of the projector. 相似文献
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单块晶体2×2光开关 总被引:9,自引:3,他引:6
利用晶体的双折射和全内双反射现象以及晶体的电光效应 ,设计了一种单块晶体集成的 2× 2光开关 ,将一个电光调制器和两个光束分束器集成到一块铌酸锂晶体上 ,实现了光束合束、偏振态调制和光束分束三种功能。根据这种光开关的工作原理 ,给出两种开关结构 ,一种是易于级联的垂直入射结构 ,另一种是有较低操作电压的倾斜入射结构 ,并对倾斜入射结构的光开关进行了制作和测试。实验结果表明 :这种集成结构的 2× 2光开关操作电压低 ,串扰小 ,能量损耗小 ,抗干扰 ,稳定可靠 ,适用于各种光学互连网络。 相似文献
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基于自相位调制和交叉相位调制的全光开关特性研究 总被引:2,自引:2,他引:0
提出一种优化含有掺铒光纤放大器的非线性Sagnac干涉仪全光开关的新方法,建立了基于自相位调制和交叉相位调制两种解析模型,讨论了掺铒光纤放大器的小信号增益和饱和输出功率对开关性能的影响.分析表明掺铒光纤放大器的性能参量对开关所需要的Sagnac环中光子晶体光纤长度产生限制.当采用相同长度的光子晶体光纤时,基于交叉相位调制方式的全光开关与基于自相位调制方式的全光开关相比能够显著降低开关功率.采用分布傅里叶法数值求解非线性薛定谔方程,优化了开关结构,讨论了重复频率为40 GHz脉宽为5 ps的高斯型信号脉冲在开关时沿Sagnac环的传输特性.模拟结果表明,通过合理选择高非线性光子晶体光纤长度和掺铒光纤放大器的性能参量能够实现超低开关功率(<1 mW)的开关操作. 相似文献
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We propose and analyze a novel photonic crystal pulse position modulator utilizing a coupled cavity waveguide delay line. Also, a nonlinear photonic crystal directional coupler is used as an all-optical switch in the proposed structure. The input data acts as the control signal of the switch and activates the switching operation. We show that the device size can be reduced significantly by designing the delay line to achieve a reduced group velocity and a quasi-flat impurity band. The size of the designed modulator is 32a × 16a, where a represents the lattice constant of the photonic crystal. The characteristics of the device are investigated by finite-difference time-domain (FDTD) and plane wave expansion (PWE) methods. 相似文献
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从实验上研究了不同外加直流电场作用下固液同成分的SBN:Cr和SBN:Rh晶体的光致折射率变化规律.测量结果表明:无外加电场作用时,晶体中的光致折射率变化不明显;若在光辐照晶体的同时,沿晶体c轴方向施加一定方向的外电场,则晶体中即刻出现显著的光致折射率变化.这种折射率变化随外加电场的增大而增大,并且电场方向不同,折射率变化的正负也不同.因而可以通过改变外加电场的极性和幅度控制SBN:Cr和SBN:Rh晶体中光致折射率的变化特性,这对于在该类晶体中制作动态光波导具有重要意义. 相似文献
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We carried out detailed calculations for photorefractive wave-mixing switches based on one of three crystals with high electro-optic coefficients, namely, BaTiO3, Strontium Barium Niobate (SBN (0.75)), and Potasium Sodium Strontium Barium Niobate (KNSBN). A comparison of results for the three crystals shows that a 0_-cut BaTiO3 crystal is suitable for a longitudinal switch and requires a voltage of about 80 for a 2-mm-thick crystal to induce sufficient phase mismatch. The electrodes must be transparent for the incident and diffracted beams. A 45_-cut SBN (0.75) crystal, however, is suitable for a lateral switch and requires a voltage of about 150 for a 1-mm-wide crystal. The electrodes do not need to be transparent. 相似文献
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1 IntroductionQ- switching Of diode-pumped lasers iS an effective technique because they provideshort duration optical pulses required for laser ranging, nonlinear studies, medidne andother important applications[1--#]. It is obvious that the replacement of an organic dyewith a solid-state one makeS a laser more convenient tO use. Semiconductor materialsare attractive for saturable absorber because Of the large optical nonlinearities that can beobtained, particularly in quantum--well .t..t..… 相似文献
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A novel design of a tunable terahertz switch and band-pass filter using liquid-crystal-filled photonic crystal waveguide is demonstrated. The effects of magnetic field on the photonic bandgaps and transmitting properties of a THz wave are investigated by using the plane wave expansion method and finite difference time domain method. The efficient photonic bandgap tuning is predicted such that the two-dimensional liquid-crystal-filled photonie crystal waveguide can serve as a switch and continuously tunable band-pass filter with controlling of the magnetic field. 相似文献
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A full resolution autostereoscopic three-dimensional (3D) display prototype is developed. It is composed of a time division thin film transistor liquid crystal display panel with an optical controlled birefringence liquid crystal polarization switch and a polarizer parallax barrier. Fast driving circuits operating at 120-Hz frame rate are fabricated. The 3D images on the display have the same resolution as the corresponding two-dimensional images, which is significantly different from conventional parallax barrier autostereoscopic 3D displays having degraded 3D image resolution. 相似文献
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REN Zhaoyu ZHUANG Dounan LEI Shizhan YU Guiqiu Zhang Jiyue 《Chinese Journal of Lasers》1995,4(3):199-206
TheExperimentStudyofTwoNd ̄(3+):p-glassRodsLaserwithaQ-switch/mode-lockingandAmplifier¥RENZhaoyu;ZHUANGDounan;LEIShizhan;YUGui... 相似文献
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In this paper, we have presented a compact and integrated terahertz wave switch design based on photonic crystal ring resonators.
The photonic crystal structure with square lattice is investigated and applied for design of ring resonators. The switching
mechanism of this novel switch is based on the variation of the resonant frequency of the ring resonator inserted between
two parallel waveguides. The refractive index of the holes of the structure filled with polyaniline electrorheological fluids
are varied by applied external electric field, the result of which is the variation of the ring resonant frequency. The proposed
device is analyzed by using finite difference time domain method. Numerical simulation results show that this switch has high
extinction ratio, small size, low voltage and advantages of selectivity of coupling THz wave to different output ports. 相似文献