title: Fiber structure to convert a Gaussian beam to higher-order optical orbital angular momentum modes.
abstract: We propose a fiber structure of a square core and ring refractive index profile that converts an input circular polarized Gaussian mode into optical orbital angular momentum (OAM) modes. By breaking the circular symmetry of the waveguide, the input circularly polarized fundamental mode in the square core can be coupled into the ring region to generate higher-order OAM modes, corresponding to the transference of spin angular momentum and orbital angular momentum. We show, by using simulation, the generation of OAM modes with a topological charge l up to 9 using <10 mm long fiber. The mode purity is above 96.4% and the extinction ratio can be 30 dB.
authors: Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA. yanyan@usc.edu
authors: Yan
authors: Y
authors: Yan
authors: Lin
authors: L
authors: Zhang
authors: Jian
authors: J
authors: Wang
authors: Jeng-Yuan
authors: JY
authors: Yang
authors: Irfan M
authors: IM
authors: Fazal
authors: Nisar
authors: N
authors: Ahmed
authors: Alan E
authors: AE
authors: Willner
authors: Samuel J
authors: SJ
authors: Dolinar