title: Controllable all-fiber orbital angular momentum mode converter.
abstract: We present a scheme to realize a controllable, scalable, low-cost, and versatile all-fiber orbital angular momentum (OAM) converter. The converter consists of a two-mode fiber (TMF) with its input terminal welded with a single-mode fiber, a mechanical long-period grating (LPG), a mechanical rotator, metal flat slabs, and a fiber polarization controller. The LPG is employed to convert the fundamental fiber mode to higher-order modes and the flat slabs are used to stress the TMF to adjust the relative phase difference between two orthogonal higher-order modes. Selective conversion from the LP(01) mode to the LP(11a), LP(11b), OAM(-1), or OAM(+1) mode is demonstrated in the experiment.
authors.forename: Shuhui
authors.initials: S
authors.lastname: Li
authors.forename: Qi
authors.initials: Q
authors.lastname: Mo
authors.forename: Xiao
authors.initials: X
authors.lastname: Hu
authors.forename: Cheng
authors.initials: C
authors.lastname: Du
authors.forename: Jian
authors.initials: J
authors.lastname: Wang