Abstract

In recent years, mode-division multiplexing (MDM) has been intensively proposed to cope with the information capacity crisis. However, how to multiplex a large number of OAM modes efficiently with low insertion loss and broad bandwidth is still a crucial issue. To solve this problem, we design a multiplexing system in which we make two functional blocks including a compactable shaper and a pair of free-form refractive optical elements. In one block, a self-designed compactable shaper is used to turn the Gaussian beam output from a single mode fiber into the elongated beams with tilted plane wave so that it can meet the phase requirement for the subsequently transformation. In the other block, a pair of free-form refractive optical elements is reversely used to multiplex multi modes based on coordinate transformations. Based on these structures, OAM multiple modes multiplexing experiment has been successfully performed in C+L band and the insertion losses of all modes are less than 1.6 dB. Furthermore, in the limited number of modes, the energy insertion loss does not increase with the increase of the number of OAM modes. The scheme offers a great potential for the integration in the next platform of MDM.

Optical communications using orbital angular momentum beams

A. E. Willner, H. Huang, Y. Yan, Y. Ren, N. Ahmed, G. Xie, C. Bao, L. Li, Y. Cao, Z. Zhao, J. Wang, M. P. J. Lavery, M. Tur, S. Ramachandran, A. F. Molisch, N. Ashrafi, and S. Ashrafi
Adv. Opt. Photon. 7(1) 66-106 (2015)

Tunable orbital angular momentum mode filter based on optical geometric transformation

Hao Huang, Yongxiong Ren, Guodong Xie, Yan Yan, Yang Yue, Nisar Ahmed, Martin P. J. Lavery, Miles J. Padgett, Sam Dolinar, Moshe Tur, and Alan E. Willner
Opt. Lett. 39(6) 1689-1692 (2014)

Discrimination of orbital angular momentum modes of the terahertz vortex beam using a diffractive mode transformer

Changming Liu, Xuli Wei, Liting Niu, Kejia Wang, Zhengang Yang, and Jinsong Liu
Opt. Express 24(12) 12534-12541 (2016)

Multicasting in a spatial division multiplexing system based on optical orbital angular momentum

Yan Yan, Yang Yue, Hao Huang, Yongxiong Ren, Nisar Ahmed, Moshe Tur, Samuel Dolinar, and Alan Willner
Opt. Lett. 38(19) 3930-3933 (2013)

Optical orbital angular momentum multiplexing communication via inversely-designed multiphase plane light conversion

Juncheng Fang, Jinpei Li, Aru Kong, Youpeng Xie, Chuxuan Lin, Zhenwei Xie, Ting Lei, and Xiaocong Yuan
Photon. Res. 10(9) 2015-2023 (2022)