涡旋光平衡探测系统转速测量精度与信噪比分析(特邀)

Analysis of rotational velocity measurement accuracy and signal-tonoise ratio of balanced detection based on vortex beam(Invited)

对于基于叠加态涡旋光和涡旋光零差探测等传统转速测量方式,光的远距离传输和发散等原因造成的信号光衰减会导致探测系统无法准确提取信号,而涡旋光平衡探测系统可以解决这一难题,但是以往的研究对该探测系统的精度和信噪比鲜有分析,这一定程度上限制了其工程化的进展。首先将零差探测系统作为对比项,通过分析不同转速下涡旋光平衡探测系统和零差探测系统测量精度的变化情况,证明了二者均可实现高精度测量,其次通过对比在不同信号光功率下二者的信噪比(SNR),发现了在测量微弱信号时涡旋光平衡探测系统具有明显优势;最后,通过分析不同本振光功率对信噪比造成的影响,揭示了平衡探测信噪比和本振光功率之间的关系,阐明了信噪比随本振光功率变化的原因。

For traditional velocity detection method like superposition state vortex beam detection and vortex beam homodyne detection, the optical attenuation of the signal caused by long-distance transmission and light divergence would lead to that the detection system can not extract the signal accurately. However, the balanced detection based on vortex beam can solve this problem. But there is little analysis about accuracy and signal-tonoise ratio(SNR) of this detection system, which limits the engineering development of the detection system to a certain extent. Firstly, the homodyne detection was set as comparative item. By analyzing the accuracy change condition of balanced detection and homodyne detection based on vortex beam under different rotational velocity,it was verified that both of them can measure accurately. Secondly, it could be found that the balanced detection had significant advantage when signal light power was low by comparing the SNR of both with different signal light power. Finally, the relation of SNR of the balanced detection and local-oscillator power was revealed by analyzing the effect of SNR on different local-oscillator powers. And the cause of SNR changing with localoscillator power was clarified.