涡旋光束的自适应光学波前校正技术研究进展(特邀)

Progress in adaptive optics wavefront correction technology of vortex beam(Invited)

涡旋光束携带了与其螺旋波前结构相关的轨道角动量,由于其在通信系统不增加带宽情形下可极大增加系统容量和频谱效率,引起了广泛关注。然而,自由空间中的湍流将导致涡旋光束的螺旋波前发生畸变,产生模间串扰,降低接收功率,从而削弱链路性能。自适应光学波前校正技术是克服干扰的有效手段之一。综述了涡旋光束的自适应光学波前校正技术的发展,阐述了Shack-Hartmann、随机并行梯度下降、Gerchberg-Saxton三种算法的校正原理,分析了深度学习在波前校正技术中的应用,并介绍了笔者课题组对水下湍流环境中波前校正技术的研究工作。

The vortex beam can carry orbital angular momentum(OAM),which is associated with the spiral wavefront structure.The vortex beam has attracted a widespread attention due to its capability to significantly increase the transmission capacity and the spectral efficiency of the communication systems without the bandwidth increase.However,the turbulence in free space will cause the distortion on the spiral wavefront,resulting in the inter-mode crosstalk and the received power reduction,that degrade the communication systems’performance.Adaptive optics is one of the effective methods to correct the distortion.The basic algorithms in adaptive optics for wavefront correction was reviewed,such as,Shack-Hartmann(SH),Stochastic-ParallelGradient-Descent(SPGD)and Gerchberg-Saxton(GS)algorithm,and the application of deep learning in wavefront correction was presented.At last,the authors’research work on the wavefront correction in underwater environment was introduced.