Yang Hongbin, Yan Qingze, Zhang Yixin, Hu Lifa
Appl Opt. 2021 Dec 10;60(35):10772-10779. doi: 10.1364/AO.442765.
We investigated the effects of absorbent and weak turbulent seawater channels on the orbital angular momentum (OAM) mode carried by perfect optical vortex (POV) based on the Rytov approximation. After deriving the received probability of OAM modes, some numerical results are worked out to show that the receiving probability of OAM modes decreases linearly with the increase of virtual refractive index of the water body. An underwater communication link with POV as the signal carrier can obtain high receiving probability by adopting long signal wavelength in intervals of "seawater window wavelength," low OAM quantum number, a POV with a larger ring radius, and a transmitter as well as receiver with a smaller aperture. The transmission distance of OAM mode carried by POV in four kinds of seawater is better than that of a Bessel-Gaussian beam.
我们基于Rytov近似研究了吸收性和弱湍流海水通道对完美光学涡旋（POV）所携带的轨道角动量（OAM）模式的影响。在推导OAM模式的接收概率后，得出了一些数值结果，表明OAM模式的接收概率随水体虚折射率的增加而线性降低。以POV作为信号载体的水下通信链路，通过在“海水窗口波长”区间采用长信号波长、低OAM量子数、具有较大环形半径的POV以及较小孔径的发射机和接收机，可以获得较高的接收概率。POV携带的OAM模式在四种海水中的传输距离优于贝塞尔 - 高斯光束。
