Optical Fiber Voltage Sensor with New Fiber Component and Optical Path Design

光学电压互感器(OVT)是一种新型的电力互感器，它克服了传统电压互感器(VT)的许多缺点，在未来的电力系统中有着广阔的应用前景，光学电压互感器经过几十年的发展，已经形成了一套相关的理论，但是依然存在有待发展和完善的问题，本文的主要研究对象为光学电压互感器的核心部分即传感头，以后均称为光学电压传感器(OVS)。本文首先介绍了偏振光在晶体与双折射光纤中传输的基本理论，并在这个基础上分析了两种不同结构的光学电压传感器：一种是创新的运用高双折射光子晶体光纤制作的四分之一波片的透射式光学电压传感器，另一种是不采用四分之一波片的新型反射式横向调制电压传感器。本文分别分析了这两种不同结构的光学电压传感器的工...Optical Voltage Transformer (OVT) is a new kind of power transformer. OVT overcomes many drawbacks of traditional voltage transformer and can be widely used in power system in the near future. After years of development, it has formed a theoretical system. However, there are still some flaws and shortcomings. The main research object in the paper is the core of OVT, sensor probes, which is called ...学位：理学硕士院系专业：信息科学与技术学院电子工程系_无线电物理学号：2005130236

An alys is and Measurement on Refractive Index Sensing of Few Mode Fiber Bragg Gratings

中文摘要：理论分析和模拟计算了少模光纤布拉格光栅基模及高阶模的耦合与传输特性,得到在相同外部折射率变化情况下,少模光纤基模与高阶模耦合对应的布拉格波长变化,比正、反向基模之间耦合对应的布拉格波长变化显著增大。实验上制作了少模光纤布拉格光栅,测量了基模之间以及基模与高阶模之间对应的布拉格波长随外部折射率、温度变化的情况,得到与理论分析相符的结果。而对于温度变化对折射率测量结果干扰的问题,提出了通过计算布拉格波长差来克服温度影响的方法。这些结果为采用布拉格光纤光栅测量外部折射率变化提供了一种新的途径。英文摘要：The coupling and propagation characteristics of fundamental modes and high－orde r modes in the few mode fiber Bragg grating was numerically analyzed and simulated. It is indicated that the shifts of the Bragg wavelength corresponding to the coupling between the fundamental mode and the backward high－order mode is obviously larger than the shift of the Bragg wavelength cor responding to the coupling between the forward and backward fundamental modes . The few mode fiber Bragg grating was fabricated , and the variations of Bragg wavelengths corresponding to fundamental modes coupling and fundamental high－order modes coupling with external refractive index and temperature were measured. The experimental results agree with the theoretical analysis . Therefore by the means of Bragg wavelength difference calculation , the temperature induced fluctuation is overcome , which presents a new ray to measure the exte rnal ref ractive index change of fibe r Bragg gratings .基金项目: 国家自然科学基金(60177026) 、厦门大学985 项目和上海市重点学科建设项目( T0102) 资助课题

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^