Author Affiliations
Abstract
1 National Engineering Laboratory for Fiber Optic Sensing Technology, Wuhan University of Technology, Wuhan 430070, China
2 School of Information Engineering, Wuhan University of Technology, Wuhan 430065, China
3 Department of Mechanical and Electrical Engineering, College of Post and Telecommunication, Wuhan Institute of Technology, Wuhan 430073, China
4 Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
We propose a novel modified frequency-shifted interferometer, where a Mach–Zehnder interferometer is added in order to obtain wavelength information. We use the Hilbert transform to extract the wavelength information from the phase of the interference pattern and construct the relationship between phase and wavelength. The laser wavelength measurement experiment is used to verify the compound interferometer. Experimental results demonstrated that our method could obtain the wavelength from the phase, which is of great significance for demodulation of the fiber Bragg grating based on a frequency-shifted interferometer.
modified frequency-shifted interferometry phase difference Hilbert transform Chinese Optics Letters
2020, 18(10): 101203
1 南京理工大学 电子工程与光电技术学院,南京 210094
2 南京理工大学 先进发射协同创新中心,南京 210094
熔融石英基片受高能激光辐照后,受热产生的热形变会恶化系统出射的光束质量。为了研究光束质量的恶化情况,采用COMSOL有限元分析软件,建立了在连续高能激光辐照下熔融石英基片热形变分析模型,并针对基片在不同的夹持方式下的热形变进行了比较分析,得到了基片受热后的温度分布和形变分布情况,并利用VirtualLab软件定量分析了熔融石英基片热形变对光束质量的影响。结果表明,采用四周固定的方式,热形变量是最小的；基片的热形变会对光束质量造成影响,激光辐照时间越长,热形变量越大,对光束质量影响越大；当基片被激光辐照20s后,采用夹板固定的基片最大形变量达到415.90nm,光束质量因子Mx2由1.0036恶化至1.4571；采用四周固定的基片最大形变量达到98.38nm,光束质量因子Mx2由1.0036恶化至1.0064。这一结果对后续激光合束系统搭建以及光束质量优化有重要的指导意义。
激光光学 热形变 有限元法 光束质量 laser optics thermal deformation finite element method beam quality
