Tunable Orbital Angular Momentum Generation Using All-Fiber Fused Coupler

• Published in: IEEE photonics technology letters Vol. 30; no. 1; pp. 99 - 102
• Main Authors: Yao, Shuzhi, Ren, Guobin, Shen, Ya, Jiang, Youchao, Zhu, Bofeng, Jian, Shuisheng
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.2018
• Subjects: All-optical devices; Couplers; fiber optics; Laser beams; Optical fiber communication; Optical fiber couplers; Optical fiber devices; Optical fiber polarization; optical vortices
• ISSN: 1041-1135; 1941-0174
• DOI: 10.1109/LPT.2017.2776981

We propose an effective approach to generate tunable orbital angular momentum (OAM) beam based on all-fiber fused coupler consisting of a single mode fiber (SMF) and a two-mode fiber. The fundamental mode in the SMF is directly coupled to the LP 11 mode group (TE 0,1 , HE 2,1 even,odd , TM 0,1 ) by appropriately phase matching the modes in ,the fiber coupler. The experimental results demonstrate that the OAM beam is produced by combining HEeven 2,1 and TE 0,1 (or HE 2,1 odd and TM 0,1 ) with a π/2 phase shift and the OAM topological charge could be tuned from l = -1 to l = +1 by adjusting a polarizer set at the output end of fiber.