Effect of Gaussian fields distribution on mixing efficiency for coherent detection
-
摘要: 在相干探测系统中,信号光与本振光在探测器上进行混频产生中频信号,实现将携带目标信息的信号光转置与放大,实现了近量子噪声限的探测方式。为了有效利用回波信号获得良好的探测性能,有必要对两束光的混频特性进行研究。信号光与本振光在探测器光敏面上的分布决定了两束光的混频效率,只有信号光与本振光的场分布完全一致探测器输出的中频光电流最大。通过对高斯光束的混频进行理论推导并进行数值模拟,结果表明混频效率对光敏面上信号光的分布较为敏感,本振光束腰半径应该等于或略大于信号光束腰的半径,探测器光敏面半径应约为本振光束腰半径的2倍。Abstract: A detectable intermediate frequency current signal is generated by mixing the signal beam with the local oscillator beam in a coherent detection system. The signal beam which carries the target information is amplified and frequency shifted to allow operation at a sensitivity that approaches the shotnoise limit. To make full use of the return signal and achieve preferable performance,the mixing characteristics should be considered. Signal and local oscillator beam incident on the surface of photodetector, and the influence of fields distribution on mixing efficiency was discussed in this paper. The highest intermediate frequency current could only be achieved when the field distribution of the signal beam was completely identical with that of the local oscillator beam. For both the signal and local oscillator were Gaussian beam coherent in different conditions, such as focus offset, beam waist differecnce and beam waist mismatch, the mixing efficiency was theoretically analyzed and numerically. Numerical simulation shows that the mixing efficiency is more sensitive to the alignment of the incident signal beam than that of the local oscillator beam, the radius of the local oscillator beam waist should be equal or slightly larger than that of the signal beam, the detector radius should be double that of the local oscillator beam waist.
-
Key words:
- coherent detection /
- mixing efficiency /
- Gaussian beam /
- numerical simulation
-
[1] [2] Pan Jingyan, Wu Shuangyang, Liu Guo, et al. Wind measurement techniques of coherent wind lidar [J]. Infrared and Laser Engineering, 2013, 42(7): 1720-1724. (in Chinese) 潘静岩, 邬双阳, 刘果, 等. 相干激光测风雷达风场测量技 术[J]. 红外与激光工程, 2013, 42(7): 1720-1724. [3] Zhang Tong, Tong Shoufeng. Effect of collimating mismatch on mixing efficiency for space coherent laser communication[J]. Journal of Changchun University of Science and Technology (Natural Science Edition), 2013, 36(1-2): 13-15. (in Chinese) 张桐, 佟首峰. 准直失配对空间相干激光通信混频效率的 影响[J]. 长春理工大学学报(自然科学版), 2013, 36(1-2): 13-15. [4] [5] Wei Guo, Zhou Jian, Long Xingwu. Analysis of signal-to-noise ratio and heterodyne efficiency for reference-beam laser Doppler velocimeter [J]. Optics Laser Technology, 2014, 44(1): 108-113. [6] [7] [8] Ma Zongfeng, Zhang Chunxi, Zhang Zhaoyang, et al. Signal-noise ratio in heterodyne detcetion [J]. Acta Optical Sinica, 2007, 27(5): 889-892. (in Chinese) 马宗峰, 张春熹, 张朝阳, 等. 光学外差探测信噪比研究[J]. 光学学报, 2007, 27(5): 889-892. [9] [10] Zhou Jian, Feng Qingqi, Long Xingwu, et al. Signal-to-noise ratio and doppler current of laser doppler velocimeter[J]. Opto-Electronic Engineering, 2009, 36 (6): 46-51. (in Chinese) 周健, 冯庆奇, 龙兴武, 等. 激光多普勒测速仪信噪比及多 普勒电流的研究[J]. 光电工程, 2009, 36(6): 46-51. [11] Ma Zongfeng, Wang Jiqiang, Luo Guangming, et al . Optimum optical local-oscillator power for all-fiber coherent lidar [J]. Semiconductor Optoelectronics, 2009(2): 286-290. (in Chinese) 马宗峰, 王纪强, 罗光明, 等. 全光纤相干激光雷达本振光 功率优化[J]. 半导体光电, 2009(2): 286-290. [12] [13] [14] Liu Hongzhan, Ji Yuefeng, Xu Nan, et al. Effect of amplitude profile differency of signal and local oscillator wave on heterodyn efficiency in the inter-satellite coherent optivcal communication system [J]. Acta Optical Sinica, 2011, 31(10): 1006001-1-6. (in Chinese) 刘宏展, 纪越峰, 许楠, 等. 信号与本振光振幅分布对星间 相干光通信系统混频效率的影响[J]. 光学学报, 2011, 31 (10): 1006001-1-6. [15] Jiang Chenghao, Yang Jinhua, Zhang Lijuan, et al. Schematic design and simulation of new Doppler imaging laser radar[J]. Infrared and Laser Engineering, 2014, 43(2): 411-416. (in Chinese) 姜成昊, 杨进华, 张丽娟, 等. 新型多普勒成像激光雷达原 理设计与仿真[J]. 红外与激光工程, 2014, 43 (2): 411-416. [16] [17] Liu Liren. Optical antenna of telescope for synthetic aperture ladar[C]//SPIE, 2008, 7094: 70940F. -
点击查看大图
计量
- 文章访问数: 229
- HTML全文浏览量: 17
- PDF下载量: 284
- 被引次数: 0
下载:
