[1] Nye JF, Berry MV. Dislocations in wave trains. Proc Roy Soc A Math Phys Eng Sci 1974; 336: 165–190. doi: 10.1098/rspa.1974.0012
[2] Dennis MR, O'Holleran K, Padgett MJ. Singular optics: optical vortices and polarization singularities. Prog Opt 2009; 53: 293–363. doi: 10.1016/S0079-6638(08)00205-9
[3] Allen L, Beijersbergen MW, Spreeuw RJC, Woerdman JP. Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes. Phys Rev A 1992; 45: 8185–8189. doi: 10.1103/PhysRevA.45.8185
[4] Zhan QW. Cylindrical vector beams: from mathematical concepts to applications. Adv Opt Photonics 2009; 1: 1–57. doi: 10.1364/AOP.1.000001
[5] Yao AM, Padgett MJ. Orbital angular momentum: origins, behavior and applications. Adv Opt Photonics 2011; 3: 161–204. doi: 10.1364/AOP.3.000161
[6] Rubinsztein-Dunlop H, Forbes A, Berry MV, Dennis MR, Andrews DL et al. Roadmap on structured light. J Opt 2017; 19: 013001. doi: 10.1088/2040-8978/19/1/013001
[7] Paterson L, MacDonald MP, Arlt J, Sibbett W, Bryant PE et al. Controlled rotation of optically trapped microscopic particles. Science 2001; 292: 912–914. doi: 10.1126/science.1058591
[8] Padgett M, Bowman R. Tweezers with a twist. Nat Photonics 2011; 5: 343–348. doi: 10.1038/nphoton.2011.81
[9] Chen R, Agarwal K, Sheppard CJR, Chen XD. Imaging using cylindrical vector beams in a high-numerical-aperture microscopy system. Opt Lett 2013; 38: 3111–3114. doi: 10.1364/OL.38.003111
[10] Meier M, Romano V, Feurer T. Material processing with pulsed radially and azimuthally polarized laser radiation. Appl Phys A 2007; 86: 329–334. doi: 10.1007/s00339-006-3784-9
[11] Elias NM II. Photon orbital angular momentum in astronomy. Astron Astrophys 2008; 492: 883–922. doi: 10.1051/0004-6361:200809791
[12] Leach J, Jack B, Romero J, Jha AK, Yao AM et al. Quantum correlations in optical angle-orbital angular momentum variables. Science 2010; 329: 662–665. doi: 10.1126/science.1190523
[13] Gibson G, Courtial J, Padgett MJ, Vasnetsov M, Pas'ko V et al. Free-space information transfer using light beams carrying orbital angular momentum. Opt Express 2004; 12: 5448–5456. doi: 10.1364/OPEX.12.005448
[14] Wang J, Yang JY, Fazal IM, Ahmed N, Yan Y et al. Terabit free-space data transmission employing orbital angular momentum multiplexing. Nat Photonics 2012; 6: 488–496. doi: 10.1038/nphoton.2012.138
[15] Milione G, Lavery MPJ, Huang H, Ren YX, Xie GD et al. 4 × 20 Gbit/s mode division multiplexing over free space using vector modes and a q-plate mode (de)multiplexer. Opt Lett 2015; 40: 1980–1983. doi: 10.1364/OL.40.001980
[16] Zhao YF, Wang J. High-base vector beam encoding/decoding for visible-light communications. Opt Lett 2015; 40: 4843–4846. doi: 10.1364/OL.40.004843
[17] Krenn M, Handsteiner J, Fink M, Fickler R, Ursin R et al. Twisted light transmission over 143 km. Proc Natl Acad Sci USA 2016; 113: 13648–13653. doi: 10.1073/pnas.1612023113
[18] Bozinovic N, Yue Y, Ren YX, Tur M, Kristensen P et al. Terabit-scale orbital angular momentum mode division multiplexing in fibers. Science 2013; 340: 1545–1548. doi: 10.1126/science.1237861
[19] Ramachandran S, Kristensen P. Optical vortices in fiber. Nanophotonics 2013; 2: 455–474. doi: 10.1515/nanoph-2013-0047
[20] Ndagano B, Brüning R, McLaren M, Duparré M, Forbes A. Fiber propagation of vector modes. Opt Express 2015; 23: 17330–17336. doi: 10.1364/OE.23.017330
[21] Wang AD, Zhu L, Chen S, Du C, Mo Q et al. Characterization of LDPC-coded orbital angular momentum modes transmission and multiplexing over a 50-km fiber. Opt Express 2016; 24: 11716–11726. doi: 10.1364/OE.24.011716
[22] Chen S, Liu J, Zhao YF, Zhu L, Wang AD et al. Full-duplex bidirectional data transmission link using twisted lights multiplexing over 1.1-km orbital angular momentum fiber. Sci Rep 2016; 6: 38181. doi: 10.1038/srep38181
[23] Zhu L, Liu J, Mo Q, Du C, Wang J. Encoding/decoding using superpositions of spatial modes for image transfer in km-scale few-mode fiber. Opt Express 2016; 24: 16934–16944. doi: 10.1364/OE.24.016934
[24] Willner AE, Huang H, Yan Y, Ren Y, Ahmed N et al. Optical communications using orbital angular momentum beams. Adv Opt Photonics 2015; 7: 66–106. doi: 10.1364/AOP.7.000066
[25] Wang J. Advances in communications using optical vortices. Photonics Res 2016; 4: B14–B28. doi: 10.1364/PRJ.4.000B14
[26] Wang J. Data information transfer using complex optical fields: a review and perspective (Invited Paper). Chin Opt Lett 2017; 15: 030005. doi: 10.3788/COL201715.030005
[27] Richardson DJ, Fini JM, Nelson LE. Space-division multiplexing in optical fibres. Nat Photonics 2013; 7: 354–362. doi: 10.1038/nphoton.2013.94
[28] Forbes A, Dudley A, McLaren M. Creation and detection of optical modes with spatial light modulators. Adv Opt Photonics 2016; 8: 200–227. doi: 10.1364/AOP.8.000200
[29] Cai XL, Wang JW, Strain MJ, Johnson-Morris B, Zhu JB et al. Integrated compact optical vortex beam emitters. Science 2012; 338: 363–366. doi: 10.1126/science.1226528
[30] Miao P, Zhang ZF, Sun JB, Walasik W, Longhi S et al. Orbital angular momentum microlaser. Science 2016; 353: 464–467. doi: 10.1126/science.aaf8533
[31] Cherchi M, Ylinen S, Harjanne M, Kapulainen M, Aalto T. Dramatic size reduction of waveguide bends on a micron-scale silicon photonic platform. Opt Express 2013; 21: 17814–17823. doi: 10.1364/OE.21.017814
[32] Ndagano B, Sroor H, McLaren M, Rosales-Guzmán C, Forbes A. Beam quality measure for vector beams. Opt Lett 2016; 41: 3407–3410. doi: 10.1364/OL.41.003407
[33] Ramachandran S, Kristensen P, Yan MF. Generation and propagation of radially polarized beams in optical fibers. Opt Lett 2009; 34: 2525–2527. doi: 10.1364/OL.34.002525
[34] Gregg P, Kristensen P, Ramachandran S. Conservation of orbital angular momentum in air-core optical fibers. Optica 2015; 2: 267–270. doi: 10.1364/OPTICA.2.000267
[35] Riesen N, Love JD, Arkwright JW. Few-mode elliptical-core fiber data transmission. IEEE Photonics Technol Lett 2012; 24: 344–346. doi: 10.1109/LPT.2011.2178825
[36] Ip E, Milione G, Li MJ, Cvijetic N, Kanonakis K et al. SDM transmission of real-time 10 GbE traffic using commercial SFP+transceivers over 0.5 km elliptical-core few-mode fiber. Opt Express 2015; 23: 17120–17126. doi: 10.1364/OE.23.017120
[37] Wang L, Ai JZ, Zhu L, Wang AD, Fu SN et al. MDM transmission of CAP-16 signals over 1.1-km anti-bending trench-assisted elliptical-core few-mode fiber in passive optical networks. Opt Express 2017; 25: 22991–23002. doi: 10.1364/OE.25.022991
[38] Ding YH, Ou HY, Xu J, Peucheret C. Silicon photonic integrated circuit mode multiplexer. IEEE Photonics Technol Lett 2013; 25: 648–651. doi: 10.1109/LPT.2013.2247394
[39] Miller DAB. Reconfigurable add-drop multiplexer for spatial modes. Opt Express 2013; 21: 20220–20229. doi: 10.1364/OE.21.020220