基于体光栅窄带光学滤波的激光雷达收发波长动态匹配技术研究

Study on dynamic wavelength matching technology of laser radar based on volume grating narrowband optical filtering

  • 摘要: 激光雷达是一种可以精确、快速获取目标三维信息的主动探测技术。然而,激光雷达在白天工作时会受到强烈的太阳背景辐射噪声的影响。此时,一般需要采用窄线宽的激光器与滤波器件配合使用,从而达到背景光抑制的效果。当两者都是极窄线宽时,如果二者中心波长产生失配,即具有一定的误差,那么接收信号的信噪比将会受到显著影响。因此,文中从窄带滤波和接收信号对发射信号的波长跟踪的角度出发,利用体光栅的相关特性设计了激光雷达的可调谐滤波接收器和收发系统光路,实现了激光雷达在窄滤波带宽条件下接收波长对发射波长的跟踪。最后,在实验室实际搭建了整个系统,验证了系统设计的正确性。在固定波长条件下与可调谐波长条件下,跟踪精度均优于2.9 pm,此时,接收信号强度大于中心波长完全匹配条件下的99.97%。

     

    Abstract: LiDAR is a kind of active detection technology that can accurately and quickly obtain 3D information of targets. However, it is subject to intense noise from the solar background when it operates during the day. In this case, narrow line width lasers and filters are generally used to achieve the effect of suppression of background noise. When both of them are extremely narrow line widths, the SNR of the received signal will be significantly affected if the center wavelengths of the two are mismatched. Therefore, from the perspective of narrowband filtering and wavelength tracking of the transmitted signal by the received signal, a tunable filter receiver and the optical path of the transceiver system of the lidar were designed by using the volume grating, and the tracking of the received wavelength to the transmitted wavelength of the lidar was realized under the condition of narrow filtering bandwidth. Finally, the whole system was actually built in the laboratory to verify the correctness of the system design. At a fixed wavelength and tunable wavelength, the tracking accuracy is better than 2.9 pm. At this time, the received signal intensity is greater than 99.97% of the central wavelength matching condition.

     

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