• Opto-Electronic Engineering
  • Vol. 49, Issue 7, 210414 (2022)
Xin Zhou1、2、3, Fan Zou1、2、3, Jiali Jiang1、2, Feng Li1、2, Chao Geng1、2、*, and Xinyang Li1、2
Author Affiliations
  • 1Key Laboratory of Adaptive Optics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
  • 2Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
  • 3University of Chinese Academy of Sciences, Beijing 100049, China
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    DOI: 10.12086/oee.2022.210414 Cite this Article
    Xin Zhou, Fan Zou, Jiali Jiang, Feng Li, Chao Geng, Xinyang Li. Research on beam steering of numerous sub-aperture fiber laser phased array[J]. Opto-Electronic Engineering, 2022, 49(7): 210414 Copy Citation Text show less

    Abstract

    Overview: Numerous sub-aperture fiber laser array is one of the emerging technologies to build high power, high beam quality and equivalent optical large aperture. Realizing the common phase and even the fast and flexible beam deflection of array laser beam based on the precise phase control is the key to the application of the current fiber laser phased array technology. In this paper, the optical phase-controlled steering technology is combined with the fiber laser coherent combining system, and the beam steering characteristics of the numerous sub-aperture, meter-scale fiber array laser coherent combining system are studied. Aiming at the development trend of numerous sub-aperture fiber laser phased array technology, based on the 19 aperture fiber laser phased array as the basic module, the meter-scale phased array transmitting system models with 19, 133 and 703 apertures are established. Based on the principle of optical phased array, the step phase folding model is adopted to make the piston phase distribution of the beam emitted from adjacent aperture change continuously, and to realize the high-precision continuous steering in a certain range. Meanwhile, the steering limit ranges of 19, 133 and 703 aperture fiber laser phased arrays are defined and calculated according to the distribution characteristics of the far-field steering beam pattern. Through numerical simulation analysis, the results show that when the piston phase difference of adjacent sub-apertures changes at equal intervals, the far-field main lobe position changes, and the steering angle gradually increases with the increase of phase difference. When the steering angle increases, the far-field main lobe energy gradually leaks into the grating lobes, which reduces the peak light intensity of the main lobe. When the peak intensity of the grating lobe is stronger than the main flap, the energy concentration of the steering beam on the far-field target surface is poor, which easily affects the position calculation of the far-field main lobe and interferes with the precise pointing control of the steering beam. Therefore, the limit range of steering is defined when the peak intensity ratio of the main lobe to the grating lobe is equal to 1. When the fiber laser phased array steers along the x- and y-axes respectively, there are obvious differences in the far-field spot shape and steering range, which is caused by the asymmetric structure of the fiber laser phased model. In this paper, the phased array models with apertures 19, 133 and 703 have equivalent diameters. As the number of sub-aperture increases, the aperture spacing decreases and the steering range increases. Therefore, the parameters of the phased array steering system can be designed according to the actual application scenario, and the aperture size and aperture number can be selected reasonably. By studying the steering characteristics of numerous sub-aperture and meter aperture fiber laser phased arrays, this paper enriches the beam wavefront control ability of fiber laser phased array technology, which can be used for precise tracking of ultra-long-distance targets and fast beam coverage in a certain range.Numerous sub-aperture fiber laser array is one of the emerging technologies to build high power, high beam quality and equivalent optical large aperture. Realizing the common phase and even the fast and flexible beam deflection of array laser beam based on the precise phase control is the key to the application of the current fiber laser phased array technology. In this paper, the optical phase-controlled steering technology is combined with the fiber laser coherent combining system, and the beam steering characteristics of the numerous sub-aperture fiber array laser coherent combining systems are studied. The beam steering is realized by changing the phase difference between the adjacent sub-aperture of the collimated laser array. The far-field steering beam pattern distribution characteristics of 19, 133 and 703 aperture fiber laser phased arrays are compared and analyzed, and the steering limit range is defined and calculated accordingly. The results provide a theoretical basis for the subsequent experimental research on the precise pointing control of fiber laser phased arrays under long-range transmission.
    Xin Zhou, Fan Zou, Jiali Jiang, Feng Li, Chao Geng, Xinyang Li. Research on beam steering of numerous sub-aperture fiber laser phased array[J]. Opto-Electronic Engineering, 2022, 49(7): 210414
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