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1.
A novel high-power polarization-independent electro-optic switch technology based on a reciprocal structure Sagnac interferometer and a transparent quadratic electro-optic ceramic is proposed and analyzed theoretically and experimentally.The electro-optic ceramic is used as a phase retarder for the clockwise and counter-clockwise polarized light, and their polarization directions are adjusted to their orthogonal positions by using two half-wave plates. The output light then becomes polarization-independent with respect to the polarization direction of the input light. The switch characteristics, including splitter ratios and polarization states, are theoretically analyzed and simulated in detail by the matrix multiplication method.An experimental setup is built to verify the analysis and experimental results. A new component ceramic is used and a nonpolarizing cube beam splitter(NPBS) replaces the beam splitter(BS) to lower the ON/OFF voltage to 305 V and improve the extinction ratio by 2 d B. Finally, the laser-induced damage threshold for the proposed switch is measured and discussed.It is believed that potential applications of this novel polarization-independent electro-optic switch technology will be wide,especially for ultrafast high-power laser systems. 相似文献
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The optical characteristics of transparent lead magnesium niobate titanate (PMNT) electro-optic ceramic, including the electro-optic phase modulation, electric hysteresis property and thermo-optic coefficient, are investigated in detail. Based on this novel ceramic, a polarization independent electro-optic switch by using fiber Sagnac interferometer (FSI) structure is realized. An initial π-shift is introduced into the Sagnac loop to eliminate the effect of the polarization orientation of the incident light on the switch performance. Then an electrically controllable PMNT phase retarder is used to switch the optical signal between the reflection and transmission ports. Some theoretical analyses are given and the switch performances are also discussed, including the thermal characteristic and different switching frequency response. 相似文献
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We propose and analyze experimentally a high-speed polarization-independent lead magnesium niobate titanate (PMNT) electro-optic switch using a π-shifted fiber Sagnac interferometer (FSI). In the proposed switch, the PMNT high-speed electro-optic ceramic is used as a phase retarder for two counterpropagating waves, which can switch the energy between the reflection and transmission ports of the FSI. Because of an initial π shift introduced into the FSI by actively adjusting the polarization controller, the power response of the switch is independent of the polarization orientation of the incident light, which induces the polarization-independent characteristic of the switch. An optical switch with cross talk lower than -25 dB and a switching time of less than 200 ns is experimentally investigated. The insertion loss and electric hysteresis property are also demonstrated. Finally, a scheme to form the n × n switch matrix is proposed. 相似文献
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L. Sirleto D. S. Hermann G. Scalia L. Komitov F. De Marco G. Abbate M. Lindgren P. Mormile G. C. Righini 《Fiber and Integrated Optics》2002,21(4):277-293
Two integrated electro-optic switches based on smectic C * ferroelectric liquid crystal (FLC) planar waveguides oriented in the bookshelf geometry have been designed and realized. In order to test the first switch, a particular waveguide structure consisting of a three-stage device, having a thin FLC film middle stage and two glass waveguides as other stages, has been designed and realized. The second one is realized by a planar waveguide with a smectic C * ferroelectric liquid crystal overlayer. In this article the design, the realization, and the experimental characterization of electro-optical switches are reported. The electro-optical behavior and the response time of both devices have been studied for different configurations for both TE and TM polarization. Our main aim was to demonstrate the feasibility of an integrated electro-optic device based on a FLC waveguide, and our experimental results provide a number of interesting indications about device optimization and practical applications. 相似文献
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一种新的偏振无关电光调制器 总被引:3,自引:3,他引:0
提出一种全新的偏振无关强度调制器设计原理.这种调制器只需要一个电光晶体,不需要辅助偏振片,电极设计和制作相当简单.采用线性电光效应耦合波理论对光在调制器中的传播行为进行详细的研究,经过理论计算,发现光通过调制器后,出射的调制光强不依赖于入射光的偏振状态.最后,以4 mm晶系中的SBN和KNSBN为例,给出调制器在横向应用时电光晶体优化切割方案. 相似文献
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A tunable Fabry-Perot (F-P) filter by using electro-optic polymer film is proposed. The electro-optic polymer is alkoxysilane dye (ASD)/SiO2-TiO2 hybrid material, whose electro-optic coefficient γ33 is about 5 pm/V. The wavelength tuning range of 3.8 nm under 400-V DC voltage and the nonlinear characteristic with the electric field have been obtained via electro-optical properties of polymer. Both of polymer film fabrication and F-P filter design have been introduced. The tunable F-P filter is designed for the application of two-input/two-output port wavelength-selective optical switch. Also, some problems have been discussed in this letter. 相似文献
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In this article, the analysis of both an integrated electro-optic switch and a continuously tunable filter based on a Bragg grating in planar waveguide with a liquid crystal overlayer is reported. The fast and bistable switching of smectic C* in the surface-stabilized liquid crystal structure has been utilized in order to investigate the possibility of realizing an integrated electro-optical switch, whereas the soft-mode of smectic A* liquid crystals, allowing a continuous modulation of extraordinary refractive index, have been utilized in order to design an integrated wavelength filter in the wavelength range of interest for optical communication. Moreover, the performance of an electro-optical router, working at the wavelength of 1.55 μm and based on the multimode interference effects together with the electro-optic effect of smectic A* liquid crystal, is theoretically and numerically discussed. 相似文献
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Wave coupling theory of quadratic electro-optic effect is developed by considering the third-order nonlinearity as a perturbation in lossless nonmagnetic centrosymmetric medium. A general solution of the resultant equations is given to describe the quadratic electro-optic effect for the electromagnetic wave propagating along an arbitrary direction with applied external electric field. The effect of the polarization state on electro-optic coupling is studied in paraelectric phase KLTN crystals. A novel application of wave coupling theory of quadratic effect is described, namely polarization rotator, which can rotate the polarization of the electromagnetic wave with an arbitrary angle. 相似文献
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In this article, the analysis of both an integrated electro-optic switch and a continuously tunable filter based on a Bragg grating in planar waveguide with a liquid crystal overlayer is reported. The fast and bistable switching of smectic C* in the surface-stabilized liquid crystal structure has been utilized in order to investigate the possibility of realizing an integrated electro-optical switch, whereas the soft-mode of smectic A* liquid crystals, allowing a continuous modulation of extraordinary refractive index, have been utilized in order to design an integrated wavelength filter in the wavelength range of interest for optical communication. Moreover, the performance of an electro-optical router, working at the wavelength of 1.55 μm and based on the multimode interference effects together with the electro-optic effect of smectic A* liquid crystal, is theoretically and numerically discussed. 相似文献
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Vitalis Musara Winston T. Ireeta Samuel K. Fosuhene Lorinda Wu Andrew W.R. Leitch 《Optik》2012,123(3):228-234
We design a polarization mode dispersion (PMD) emulator capable of adjusting first-order (FO-) and second-order (SO-) PMD statistics, making it capable to mimick differerent fibre links or fibre plants. The emulator can adjust PMD statistics by controlling mode coupling angles between polarization maintaining fibres (PMFs) of fixed length using its seven rotatable electro-optic polarization rotators which act as half waveplates (HWPs). The stability and repeatability of the emulator under a stable laboratory environment makes PMD statistics reproducible. The control mechanism of the emulator is in real-time. 相似文献
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氦气压强对单脉冲过程电光开关特性影响的数值分析 总被引:1,自引:0,他引:1
根据单脉冲过程电光开关气体放电的微观物理过程,提出了氦气放电的一维数值模型。用数值方法分析了气压对单脉冲过程电光开关的气体击穿、放电电流、KDP晶体两侧电压、开关效率、开关速度、等离子区电子温度及等离子体浓度的影响。数值计算结果表明,气压主要影响开关速度的快慢,而对开关效率的大小影响作用不大。在相同开关脉冲的驱动下,在气压较低的情况下,开关速度随气压增大而变快;而在气压较高的情况下,开关速度随气压增大而变慢。由此得到口径为8cm×8cm电光开关的最佳工作气压为1-4 kPa的结论。 相似文献
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A novel beam-steering external cavity diode laser using an intracavity lead lanthanum zirconate titanate(PLZT) electro-optic ceramic deflector is proposed and demonstrated experimentally.The laser consists of a semiconductor laser with single mode fiber coupled output,polarization controller,PLZT electro-optic ceramic deflector,and output concave mirror.By applying proper driven electrical signals on the PLZT electro-optic deflector,the beam deflection angle achieves 5.8 mrad at 1 000 V.A high-speed beam-steering property with less than 120-ns switching time is also observed.Moreover,a good beam quality with Gaussian spatial profile and a linear polarization state are obtained. 相似文献
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A. T. Efremidis N. C. Deliolanis C. Manolikas E. D. Vanidhis 《Applied physics. B, Lasers and optics》2009,95(3):467-473
The photorefractive crystals of the sillenite family (Bi12SiO20 or BSO, Bi12GeO20 or BGO, and Bi12TiO20 or BTO) that belong to the cubic 23 point group are optically active, and exhibit the piezoelectric, elasto-optic, electro-optic
and electrogyration effect. In this paper we measure the dispersion of the electro-optic coefficient for all the crystals
of the sillenite family in the visible spectral range (500–800 nm). For this we measure by ellipsometry the polarization properties
of a beam transmitted in the transverse configuration under the action of an externally applied field. The experimental data
are fitted with an analytical expression of the beam polarization to find the electro-optic coefficient. The results show
a normal dispersion of the electro-optic coefficient in all three sillenite crystals, similarly to other electro-optic crystals. 相似文献
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电控径向双折射滤波器的横向超分辨与轴向扩展焦深 总被引:1,自引:0,他引:1
提出利用电控径向双折射光瞳滤波器实现横向超分辨性能参量的调制与轴向扩展焦深。该光瞳滤波器由两个平行偏光镜,一个电光晶体与一个径向对称双折射晶体组成。分析了电光晶体与径向双折射元件对光偏振态的空间调制作用,通过控制电光晶体的相位延迟实现径向中心处初始偏振态的控制,与径向双折射元件横向偏振态调制结合,实现了庞加莱球上偏振态演变路径与阶段的控制,从而对焦点附近偏振态进行空间调制以实现光强的重新分布。研究结果表明,外加电场调制可以实现横向上超分辨性能的调控以及轴向上焦深的扩展,并可得到相应的电光相位延迟范围。 相似文献
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C.-T. Zheng C.-S. Ma X. Yan X.-Y. Wang D.-M. Zhang 《Applied physics. B, Lasers and optics》2010,98(2-3):511-521
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. 相似文献