基于Pockels电光效应的电压方向测量

为了实现在光学电压互感器中电压方向的测量,利用Pockels效应和偏振光理论进行理论分析和实验验证,提出了一种基于Pockels效应的电压方向测量方法,得到不同方向的电压与出射光偏振态、光传播方向之间的关系。结果表明,当施加的电压值为100 V时,迎着光观测,透射光的长轴和短轴分别位于空间角度20°和110°,再通过λ/4波片后的光偏振方向位于坐标的二、四象限,可判断透射光是右旋椭圆偏振光,电压方向沿光传播方向;长轴和短轴分别位于角度130°和40°的透射光通过λ/4波片后的光偏振方向位于一、三象限,则透射光是左旋椭圆偏振光,电压方向则沿光传播的相反方向。实验结果与理论分析相符,可指导设计既能测量电压大小又能判断其方向的光学电压互感器。

LIGHT MODULATION COMBINING POCKELS EFFECT WITH FARADAY EFFECT AND ITS FUNCTIONS

With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transmitted light through the optical analyzer of various composition of electro-optical effect with magneto-optical effect are derived. The results show that the output beam from the analyzer carries information on current (or magnetic field), voltage (or electric field), active power and apparent power. When the light beam transmitted through the analyzer are transformed into electric signals, three kinds of information are included: the DC term corresponding to an active power, the term with frequency ω(50 Hz) corresponding to current or voltage, and the term with frequency 2ω(100 Hz) corresponding to an apparnt power.So, we can use the electric filter circuit to pick out the DC component for measuring active power; to pick out the component with frequency ω(50 Hz) for measuring current or voltage; and to pick out the component with frequency 2ω(100 Hz) for measuring apparent power. The paper discusses what quantities are measured when the analyzer is set on certain definite values, and ponts out the optimum selection for various measurements.

基于纵向Pockels效应的光学电压互感器

对纵向和横向Pockels效应进行了比较,介绍了采用纵向Pockels效应制作光学电压互感器的关键技术,并对双光路输出的纵向Pockels器件进行了实验,实验结果表明该纵向Pockels器件在200～600V范围内的测量准确度优于0.2%。与精密分压器配合使用,可用做高压下的电压互感器。

用 Pockels 探头进行套管尾部油中电场测试技术的研究

研制开发了一套充油电力设备油中电场测试系统．该系统的传感探头采用了ＰＯＣＫＥＬＳ电光晶体，探头输出信号经光纤输入微机进行数据采集与处理，应用该系统分别对平板电极之间、模型小套管尾部及２２０ｋＶ电容式变压器套管尾部油中部分的高压电场进行了测试，经与计算结果对比，证明了测试结果的正确性．

Pockels效应表面电荷测量中电荷反演算法的研究

Pockels效应表面电荷测量技术以其特有的技术优势逐步用于表面放电和等离子体的研究,然而如何准确获取表面电荷分布仍然是一个重要的研究课题。对Pockels效应表面电荷测量技术中的表面电荷反演算法进行研究,采用二维傅里叶变换将测量信号和表面电荷的复杂关系转换到频域中进行计算,并采用维纳滤波算法进行信号处理。计算结果和传统算法的计算结果进行了对比,结果表明,改进算法在数值计算过程中考虑材料厚度、介电特性及不同位置电荷影响等因素,计算方法更为合理。该方法可用于不同材料表面电荷的测量计算。另外,算法中维纳滤波器是计算算法中关键的组成部分,对降低系统噪声,提高数值计算的稳定性能够起到很重要的作用。

基于Pockels效应的大气电场测量研究

为解决常用场磨式大气电场仪体积大、机械磨损严重、易受电磁干扰、测量带宽窄等问题,在研究分析Pockels效应原理的基础上,提出应用Pockels效应来测量大气电场的方法。对晶体、光源的选择及传感器设计中出现的问题进行了分析,设计了一种基于Pockels效应原理的脉冲电场传感器,该传感系统包括稳定高效的光源、Pockels晶体探头、数据采集及处理电路。通过模拟仿真,说明了这种测量方法是可行的,为进一步研制大气电场测量传感器,提高其性能提供了理论依据。

Pockels效应对布里渊散射张量的修正

从电磁场方程和压电本构方程出发。借助于准静态近似的物理图像，导出了压电晶体中准静电场的表达式。给出了Ｐｏｃｋｅｌｓ效应对布里渊散射张量修正的一般形式．对１９种非中心对称点群晶体的高对称方向纯模作了具体计算，并对结果作了讨论．

电光晶体的Pockels效应仿真研究

结合麦克斯韦方程组建立了光在电光晶体中传播的数学模型;通过有限元仿真分别建立了铌酸锂晶体和锗酸铋晶体的物理参数模型,提出了一种通用的入射光三维波动场仿真方法,该方法将晶体内部电场分布和电光效应耦合波理论相结合,计算了在横向调制下两种晶体的Pockels效应,其结果与理论差值在10-5数量级内;同时,仿真结果表明,铌酸锂晶体的Pockels效应更为明显。最后对两种不同材质的电光晶体进行了0~1 000 V直流加压实验,实验表明铌酸锂晶体的Pockels效应测量精度优于±2.9%。该方法为光学电压传感器电光晶体的选择和性能评估提供了新的研究思路与理论参考。

Calibration Algorithm of Surface Charge Density on Insulating Materials Measured by Pockels Technique

Surface charges greatly affect the discharge/flashover development process across an insulator. The relationship between surface charge distribution on insulating materials and measurement data based on Pockels technique is discussed, and an improved algorithm is built to calculate the real surface charge density from original data. In this algorithm, two-dimensional Fourier transform technique and Wiener filter are employed to reduce the amount of numerical calculation and improve the stability of computation, Moreover, this algorithm considers not only the influence of sample＇s thickness and permittivity, but also the impact of charges at different positions. The achievement of this calibration algorithm is demonstrated in details. Compared with traditional algorithms, the improved one supplies a better solution in the calibration of surface charge distribution on different samples with different thickness.

High-speed 2 × 2 silicon-based electro-optic switch with nanosecond switch time

A 2 × 2 electro-optic switch is experimentally demonstrated using the optical structure of a Mach-Zehnder interferometer （MZI） based on a submicron rib waveguide and the electrical structure of a PIN diode on silicon-on-insulator （SOI）. The switch behaviour is achieved through the plasma dispersion effect of silicon. The device has a modulation arm of 1 mm in length and cross-section of 400 nm×340 nm. The measurement results show that the switch has a VπLπ figure of merit of 0.145 V.cm and the extinction ratios of two output ports and cross talk are 40 dB, 28 dB and -28 dB, respectively. A 3 dB modulation bandwidth of 90 MHz and a switch time of 6.8 ns for the rise edge and 2.7 ns for the fall edge are also demonstrated.

利用POCKELS效应对超快电信号进行无扰测量

本文提出了一种对具有重复频率的超快电信号的测量技术。利用Ｐｏｃｋ－ｅｌｓ效应，可对二维平面的高速器件的超快电信号进行无损无扰取样测量，其时间分辩率远超过目前世界上最高水平的取样示波器。本文阐述了此系统的原理及应用，并着重对系统的性能进行分析，指出它的实现可望成为测量快速电信号的一种新型技术。

The Fundamental Mechanism for the Collision/Pressure Induced Optic Effect

In this work, the fundamental mechanism regarding the collision and pressure induced optic effect is elucidated. Based on the concept of the collision-relaxation/the pressure-release induced optic effect put forth here, a new laser technology may be developed. Furthermore, our work also makes the understanding the photon involved chemical reaction become much clear and rationalized.

Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave＇s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are considered.Influences of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer boundary conditions in a wide-spectrum laser.

光学电压传感器温度响应特性分析与实验研究

光学电压传感器面临温度稳定性问题。本文以BGO晶体的Pockels效应模型为基础,结合热光效应等推导出光学电压传感器在多物理场作用下的温度响应模型,并对输出信号进行频谱分析,得到温度对传感器输出的影响规律,即由温度引起的输出漂移属于低频分量。在卡尔曼滤波降噪的基础上,提出了一种基于频谱分析的高通滤波温度补偿方法,通过滤除低频分量提高温度稳定性,并进行标定实验和温度响应特性实验。实验结果表明,传感器在[0℃,50℃]温度范围内输出电压测量精度优于±1.79%,与同平台下BP神经网络温度补偿方法进行对比,该方法易于实现且有效地抑制了温度漂移的影响。

表面电荷对介质阻挡放电发展的影响

大气压介质阻挡放电(dielectric barrier discharge,DBD)中介质表面电荷分布对放电特性和放电形态演变具有重要影响,该文通过建立基于Pockels效应的高速表面电荷测量系统,研究放电起始后连续周期内介质表面电荷动态发展过程,并分析表面电荷分布对放电形态演化过程的影响。研究表明:在起始放电后几个周期内表面电荷斑位置不固定,电荷斑直径变化范围为1.5~2.5mm,且首次放电的表面电荷量高于后续放电;随着放电的发展,正表面电荷密度降低,负表面电荷密度升高,在放电逐渐稳定的过程中,正负表面电荷相互中和,电荷分布逐渐集中,最终使得电荷斑的位置、大小与放电量维持在一种稳定状态,正负表面电荷位置固定且重合度高,即表面电荷的记忆效应对平板电极中放电丝的稳定起到了重要作用。研究结果有助于理解表面电荷在放电形态演化中的作用机制。

Potassium tantalate niobate crystals:Efficient quadratic electro-optic materials and their laser modulation technology

Electro-optic(EO)crystals are important material for all-solid-state laser technology,which can be used to fabricate various laser modulators,such as EO switches,laser deflectors,and optical waveguide.The improvements in new high-efficiency EO crystal materials have held great significance to the development of laser technology.Potassium tantalate niobate(KTN)is a popular multifunctional crystal because of its remarkable and excellent quadratic EO effect.KTN EO modulation technology offers numerous advantages,such as high efficiency,good stability,a quick response time,and inertia-free characteristics.In this paper,we summarize the research progress of KTN series crystals systemically,including the theoretical exploration on quadratic EO effect,solid-melt crystal growth technique,comprehensive physical characterization,new physical effect and mechanisms exploration,new EO devices development and design.The EO modulation technique based on the Kerr effect of KTN series crystal offers obvious advantages in reducing the drive voltage and device size,which could better meet the developmental needs of future lasers with a wide wavelength,miniaturization,and integration.This may provide theoretical guidance and an experimental basis for the design and development of new EO crystal devices and promote the development of laser technology.

工频电压下聚乙烯表面动态电荷分布的研究

聚合物材料被广泛应用于电气设备的电气隔离和机械支撑中,在高压电场作用下,大量积聚在聚合物表面的电荷会引发局部电场畸变和沿面闪络,威胁设备安全。文中搭建了具有反射式拓扑结构的Pockels效应表面电荷动态测量平台,原位观测了单极性电压、单周期工频电压和多周期工频交流电压作用下聚乙烯薄膜表面电荷二维分布的动态演变。结果表明,基于Pockels效应的测量方法可以观测到0.5 s内的电荷积聚、扩散和消散过程,这是机械扫描式的静电探头法无法获得的;在正极性和负极性电压作用下,聚乙烯表面只沉积对应极性的电荷,其积聚、扩散和消散过程的持续时间大约为0.5 s,70%~85%积聚电荷量会在0.4 s内消散。对比施加不同极性起始的正弦交流电压情况下聚乙烯表面电荷演变,发现仅正极性起始的工况下会出现正负电荷共存的分布样貌。通过观测连续10个工频周期下聚乙烯表面电荷的行为,发现聚合物表面电荷积聚至少需要经历3~4个工频周期才能稳定,在此过程中表面电荷分布区域逐渐收缩。该研究结果对于直观理解交流电压作用下聚合物电荷积聚的演变过程有重要的参考价值。

The effect of conductor loss on half-wave voltage and modulation bandwidth of electro-optic modulators

In this paper, we theoretically deduce the expressions of half-wave voltage and 3-dB modulation bandwidth in which conductor loss is taken into account. The results suggest that it will affect the theoretical values of half-wave voltage and bandwidth as well as the optimized electrode's dimension whether considering the conductor loss or not. As an example, we present a Mach-Zehnder (MZ) type polymer waveguide amplitude modulator. The half-wave voltage increases by 1 V and the 3-dB bandwidth decreases by 30% when the conductor loss is taken into account. Besides, the effects of impedance mismatching and velocity mismatching between microwave and light wave on the half-wave voltage, and 3-dB bandwidth are discussed.

Discrete spatial solitons formed in periodically poled lithium niobate by electro-optical effect

We report the numerical observation of discrete spatial solitons in a periodically poled lithium niobate waveguide array by applying an electrical field through electro-optical effect. We show that discrete spatial soliton can be controlled by applied voltage in the periodically poled lithium niobate.

面向智能电网的先进电压电流传感方法研究进展

电压电流传感测量在电力系统的电能计量、继电保护、过电压在线监测、智能设备控制、电力检修等领域均具有极其重要的地位。随着中国智能电网的加速建设以及电网数字化、智能化和自动化程度的不断提高,电压电流传感器将面临数字化、小型化及便捷化的发展需要。相比较于传统电磁式互感器,基于电光(磁光)、逆压电(磁致伸缩)、热电效应等原理的先进电压电流测量技术在电磁免疫、无损传输、拓扑结构、宽幅值和宽频带测量等方面具有各自的优势;另一方面,针对未来电网多场景应用,传感器的封装、高精度和高可靠安全运行也面临巨大挑战。因此,从电压测量和电流测量耦合机制方面,分别介绍了基于电光效应、逆压电效应和电致发光效应的电压/电场传感技术,以及基于法拉第效应、磁致伸缩、热效应和磁阻效应的电流/磁场传感技术,同时总结了相应传感材料和拓扑结构。在此基础上,指出电压电流传感在传感方式、频率特性、大气参数适应性、传感器取能、传感设备的小型化等方面面临的挑战,需要新的物理量耦合机制指引、新型先进传感材料支援和新颖有效传感器拓扑协助;性能稳定、准确度高且成本低的新型电压电流传感技术能够广泛应用于智能电网建设。