Opto-Electronic Engineering, Volume. 51, Issue 2, 230211(2024)

Decoupling study and noise analysis of multi-degree-of-freedom deformation measurement method for space gravitational wave detection telescope

Jian Luo, Jie Song, Sijun Fang, Fanle Kong, and Yong Yan*
Author Affiliations
  • MOE Key Laboratory of TianQin Mission, TianQin Research Center for Gravitational Physics & School of Physics and Astronomy, Frontiers Science Center for TianQin, Gravitational Wave Research Center of CNSA, Sun Yat-sen University (Zhuhai Campus), Zhuhai, Guangdong 519082, China
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    Figures & Tables(16)
    Schematic diagram of the composition of a three-degree-of-freedom deformation measurement system
    Schematic diagram of the three-degree-of-freedom deformation measurement system
    Schematic diagram of measurement point position selection
    Schematic diagram of the decoupling mathematical model for the three-degree-of-freedom deformation measurement system
    Zemax optical system simulation
    Relationship between displacement and phase
    (a) Schematic diagram of the actual measurement path; (b) Zemax optical path modeling diagram
    Laser frequency noise background
    Laboratory temperature and vibration level. (a) Temperature test chart; (b) Vibration test chart
    NI data acquisition card noise background
    Photodetector noise background
    Background noise of the single chain interferometer
    • Table 1. Advantages and disadvantages of multiple-degree-of-freedom measurement methods

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      Table 1. Advantages and disadvantages of multiple-degree-of-freedom measurement methods

      方法优点缺点
      电学法[20]电容测量精度高、稳定性好、测量速度快、反应时间快无法实现非接触测量,测量范围小
      电感测量精度高、对工作环境要求低
      光学法[21]光杠杆测量原理简单,易操作,稳定性高灵敏度低
      多路干涉响应速度快,灵敏度在1 mHz以上占有优势,测量范围更大,角度测量非线性更小结构复杂,对环境敏感,对结构复杂微 变形的测量和表征能力有限
      差分波前角度测量简单高效只能进行角度测量且精度受限于探测器
    • Table 2. Test the relationship between the rigid body displacement of the mirror and the phase difference received by the photodetector

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      Table 2. Test the relationship between the rigid body displacement of the mirror and the phase difference received by the photodetector

      相对位移相位差
      PD1PD2PD3
      初始位置000
      沿光轴方向+z平移20 nm0.470.470
      Rx方向旋转1.7 µrad0.660.470.61
      垂直光轴方向+y平移20 nm000.30
    • Table 3. Error sensitivity analysis of the measurement system with multiple degrees of freedom

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      Table 3. Error sensitivity analysis of the measurement system with multiple degrees of freedom

      自由度比值
      zdI : S : α = 1 : 0 : 0
      RxdI : S : α= 10000 : 1 : 0
      ydI : S : α= 10000 : 1 : 1
    • Table 4. Allocation and requirements of optical path noise indicators for the telescope deformation measurement system

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      Table 4. Allocation and requirements of optical path noise indicators for the telescope deformation measurement system

      测量系统组成部分主要噪声源噪声分配 (nm/Hz1/2@1 mHz)备注
      激光光源激光频率噪声3要求激光频率噪声δf小于4.2×107<Hz/Hz1/2@1 mHz
      前端光程耦合噪声声光调制耦合噪声1等效位移噪声<1 nm/Hz1/2@1 mHz
      光纤温度耦合噪声2光纤温度波动δT≤15 mK/Hz1/2@1 mHz
      集成光学 器件平台温度位移耦合噪声8温度位移耦合系数dS/dT=70 nm/K,测试环境温度波动δT≤15 mK/Hz1/2@1 mHz
      振动位移耦合噪声2振动位移耦合系数dS/dx=0.3×10−3 m/m,测试环境振动波动δX≤1×10−3 m/s /Hz1/2@1 mHz
      空气折射率噪声2温度波动δT≤15 mK/Hz1/2@1 mHz
      偏振噪声2等效位移噪声<2 nm/Hz1/2@1 mHz
      杂散光噪声3控制杂散光强度相较于主光束低于−20 dB
      信号采集 数据处理探测器耦合噪声1相对强度噪声需低于−100 dB/Hz@1 mHz
      相位读取噪声0.01要求相位计等效位移本底噪声是0.01 nm/Hz1/2@1 mHz
      测量系统总体噪声10
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    Jian Luo, Jie Song, Sijun Fang, Fanle Kong, Yong Yan. Decoupling study and noise analysis of multi-degree-of-freedom deformation measurement method for space gravitational wave detection telescope[J]. Opto-Electronic Engineering, 2024, 51(2): 230211

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    Paper Information

    Category: Research Articles

    Received: Aug. 30, 2023

    Accepted: Feb. 7, 2024

    Published Online: Apr. 26, 2024

    The Author Email: Yan Yong (闫勇)

    DOI:10.12086/oee.2024.230211

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