title: Phase correction for a distorted orbital angular momentum beam using a Zernike polynomials-based stochastic-parallel-gradient-descent algorithm.
abstract: A stochastic-parallel-gradient-descent algorithm (SPGD) based on Zernike polynomials is proposed to generate the phase correction pattern for a distorted orbital angular momentum (OAM) beam. The Zernike-polynomial coefficients for the correction pattern are obtained by monitoring the intensity profile of the distorted OAM beam through an iteration-based feedback loop. We implement this scheme and experimentally show that the proposed approach improves the quality of the turbulence-distorted OAM beam. Moreover, we apply phase correction patterns derived from a probe OAM beam through emulated turbulence to correct other OAM beams transmitted through the same turbulence. Our experimental results show that the patterns derived this way simultaneously correct multiple OAM beams propagating through the same turbulence, and the crosstalk among these modes is reduced by more than 5 dB.
authors.forename: Guodong
authors.initials: G
authors.lastname: Xie
authors.forename: Yongxiong
authors.initials: Y
authors.lastname: Ren
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
authors.forename: Martin P J
authors.initials: MP
authors.lastname: Lavery
authors.forename: Nisar
authors.initials: N
authors.lastname: Ahmed
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Changjing
authors.initials: C
authors.lastname: Bao
authors.forename: Long
authors.initials: L
authors.lastname: Li
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.forename: Yinwen
authors.initials: Y
authors.lastname: Cao
authors.forename: Moshe
authors.initials: M
authors.lastname: Willner
authors.forename: Moshe
authors.initials: M
authors.lastname: Tur
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Dolinar
authors.forename: Robert W
authors.initials: RW
authors.lastname: Boyd
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Shapiro
authors.forename: Alan E
authors.initials: AE
authors.lastname: Willner