离焦对激光通信接收视场的影响分析

Analysis of the influence of defocus on the field of view of laser communication reception

为了降低自由空间激光通信中对准难度,本文提出了采用离焦的方法以增大接收视场角。以满足通信所需最低能量(-35 d Bm)为基准,理论推导了探测器接收能量、接收视场角(FOV)、离焦接收能量及离焦量之间的相互关系,并通过Matlab仿真,分析对比了离焦接收能量和离焦量对接收视场角的影响。结果显示,当离焦量为0.5 mm时,离焦接收能量从-20.9 d Bm提高到-4.1 d Bm,接收视场角能增大0.27 mrad;当离焦接收能量为-4.1 d Bm时,离焦量从0.2 mm扩大到1.0 mm,视场角能增大1.75 mrad。通过对比表明,提高离焦接收能量以及扩大离焦量都可以增加接收视场角,且扩大离焦量的效果相对比较明显,这对后续离焦系统的设计提供了理论指导依据。

A defocus method is proposed in this paper to increase the receiving field of view and reduce the difficulty of alignment in free space laser communication.Based on the minimum energy required for communication(-35 dBm),the relationship between detector receiving energy,receiving field of view(FOV),defocus receiving energy and defocusing amount is theoretically derived and simulated by Matlab.We analyses and compare the influence of defocused receiving energy and defocusing on the received field of view.The results show that when the defocusing amount is 0.5 mm,the defocus receiving energy is increased from-20.9 dBm to-4.1 dBm,the receiving FOV can be increased by 0.27 mrad.When the defocus receiving energy is-4.1 dBm,the defocus amount is increased from 0.2 mm to 1.0 mm,the FOV will be increased by 1.75 mrad.The comparison shows that increasing the defocus receiving energy and expanding the defocusing amount can increase the receiving field of view,and the effect of expanding the defocusing amount is relatively significant,which provides a theoretical guidance for the design of the subsequent defocusing system.