Design of athermalization optical machine structure for optical axis stability detection system
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摘要:
在星地领域,激光通讯设备的发射光轴和接收光轴的对准度至关重要,而温度变化会导致光学元件和机械结构变形,影响光轴对准度,使系统探测精度降低。针对这一问题,本文设计了一种用于探测的高精度光轴稳定系统,根据宽波段和共轭成像的技术要求,使用具有像传递的离轴反射式开普勒望远系统压缩光束,经过分光镜后分别进入到探测子单元中,并设计了长焦距光轴稳定探测系统以提高探测精度;为校正反射系统的热差,根据光学被动无热化技术利用折射镜组补偿反射镜组的热致像差;设计机械结构并进行有限元分析;对有限元数据进行处理并带回到光学软件中仿真温度变化引起的光轴偏移角度;最后搭建平台进行验证。结果表明:光轴稳定探测系统在−10 °C时光轴偏移角度为3.90″,在45 °C时光轴偏移角度为4.23″,降低了温度变化对光轴偏移的影响。
Abstract:The alignment accuracy of the emitting and receiving optical axes of laser communication equipment in the satellite ground field is crucial. Temperature fluctuation can cause deformations of optical components and mechanical structures, affecting the optical axis’ alignment and reducing the system’s detection accuracy. We design a high-precision optical axis stability system for detection. First, according to the technical requirements of broadband and conjugate imaging, an off-axis reflective Keplerian telescope system with image transfer was applied to compress the beam. After passing through a beam splitter, the beams entered the detection subunit separately. A long focal length optical axis stability detection system was designed to improve detection accuracy. To correct the thermal difference of the reflective system, an optical passive non-thermalization technique was employed using a refractive mirror group to compensate for the thermal-induced aberration of the reflective mirror group. The mechanical structure was designed and subjected to finite element analysis. Finite element data were processed and fed into optical software to simulate the optical axis deviation angle caused by temperature fluctuation. Finally, experiments were conducted for validation. The results show that the optical axis stability detection system has an optical axis deviation angle of 3.90" at −10 °C and 4.23" at 45 °C, reducing the impact of temperature fluctuation on optical axis deviation.
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表 1 本文光学系统技术指标
Table 1. Technical specifications of the proposed optical system
指标 参数 波长 (1064±3) nm&(632.8±3) nm 视场 ±3′ 通光口径 165 mm 光轴偏移精度 ±5″ 光轴稳定探测单元艾里斑直径 ≥6个像素@1 064 nm 辅助装调系统像素数 380×380 工作温度 −10 °C~45 °C 表 2 45 °C时主次镜的相对位移量
Table 2. The relative displacement between the primary and secondary mirrors at 45 °C
参数 相对位移 X方向倾斜(°) 0.012 Y方向偏心(mm) −0.01097 Z方向偏心(mm) 0.01108 表 3 −10 °C时主次镜的相对位移量
Table 3. The relative displacement between the primary and secondary mirrors at −10 °C
参数 相对位移 X方向倾斜(°) 0.011 Y方向偏心(mm) 0.00275 Z方向偏心(mm) −0.02416 表 4 45 °C时光轴偏移量
Table 4. Optical axis offset at 45 °C
参数 值 x方向光轴偏移角度(°) −0.000982 y方向光轴偏移角度(°) −0.000581 光轴偏移(°) 0.001141(4.11″) 表 5 −10 °C时光轴偏移量
Table 5. Optical axis offset at −10 °C
参数 值 x方向光轴偏移角度(°) −0.000893 y方向光轴偏移角度(°) 0.000591 光轴偏移角度(°) 0.001071(3.86″) -
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