[1] Franke-Arnold S, Allen L, Padgett M. Advances in optical angular momentum[J]. Laser & Photonics Reviews, 2, 299-313(2008). http://onlinelibrary.wiley.com/doi/10.1002/lpor.200810007/pdf

[2] Beijersbergen M W, Spreeuw R J, Allen L et al. Multiphoton resonances and Bloch-Siegert shifts observed in a classical two-level system[J]. Physical Review A, 45, 1810-1815(1992). http://www.ncbi.nlm.nih.gov/pubmed/9907166

[3] Gibson G, Courtial J, Vasnetsov M et al. Free-space information transfer using light beams carrying orbital angular momentum[J]. Optics Express, 12, 5448-5448(2004). http://europepmc.org/abstract/med/19484105

[4] Lü Hong, Ke Xizheng. Research on the beam with orbital angular momentum used in encoding and decoding of optical communication[J]. Acta Optica Sinica, 29, 331-335(2009).

[5] Ke Xizheng, Guo Xinlong. Realization of optical phase information encode by using orbital angular momentum of light beam[J]. Chinese Journal of Quantum Electronics, 32, 69-76(2015).

[6] Beijersbergen M, Coerwinkel R, Kristensen M et al. Helical-wavefront laser beams produced with a spiral phase plate[J]. Optics Communications, 112, 321-327(1994). http://www.sciencedirect.com/science/article/pii/0030401894906386

[7] Xu Yun, Yu Junjie, Han Xiahui et al. Acousto-optically Q-switched and vortex Nd…YAG laser by using circular dammann grating for annular pumping[J]. Chinese J Lasers, 43, 0601002(2016).

[8] Curtis J E, Grier D G. Modulated optical vortices[J]. Optics Letters, 28, 872-874(2003).

[9] Ke Xizheng, Xu Junyu. Interference and detection of vortex beam with orbital angular momentum[J]. Chinese J Lasers, 43, 0905003(2016).

[10] Heckenberg N. McDudff R, Smith C, et al. Generation of optical phase singularities by computer-generated holograms[J]. Optics Letters, 17, 221-223(1992).

[11] Alexeyev A N, Fadeyeva T A, Volyar A V et al. Optical vortices and the flow of their angular momentum in a multimode fiber[J]. Semiconductor Physics, Quantum Electronics & Optoelectronics, 1, 82-89(1998). http://www.researchgate.net/publication/266498885_Optical_vortices_and_the_flow_of_their_angular_momentum_in_a_multimode_fiber

[12] Viswanathan N K. Switchable vector vortex beam generation using an optical fiber[J]. Optics Communications, 283, 861-864(2010). http://www.sciencedirect.com/science/article/pii/S0030401809011043

[13] Fang Z, Yao Y, Xia K et al. Vector mode excitation in few-mode fiber by controlling incident polarization[J]. Optics Communications, 294, 177-181(2013). http://www.sciencedirect.com/science/article/pii/S003040181201509X

[14] Zhang W D, Huang L G, Wei K Y et al. High-order optical vortex generation in a few-mode fiber via cascaded acoustically driven vector mode conversion[J]. Optics Letters, 41, 5082-5085(2016). http://www.ncbi.nlm.nih.gov/pubmed/27805691

[15] Wong G K L, Kang M S, Lee H W et al. . Excitation of orbital angular momentum resonances in helically twisted photonic crystal fiber[J]. Science, 337, 446-449(2012). http://www.ncbi.nlm.nih.gov/pubmed/22837523

[16] Li S, Wang J. A compact trench-assisted multi-orbital-angular-momentum multi-ring fiber for ultrahigh-density space-division multiplexing (19 rings×22 modes)[J]. Scientific Reports, 4, 3853(2014). http://pubmedcentralcanada.ca/pmcc/articles/PMC3900931/

[17] Zhang X Q, Wang A T, Chen R S et al. Generation and conversion of higher order optical vortices in optical fiber with helical fiber bragg gratings[J]. Journal of Lightwave Technology, 34, 2413-2418(2016). http://ieeexplore.ieee.org/document/7421936/

[18] Brunet C, Rusch L A. Optical fibers for the transmission of orbital angular momentum modes[J]. Optical Fiber Technology, 31, 172-177(2016). http://adsabs.harvard.edu/abs/2017OptFT..35....2B

[19] Grosjean T, Sabac A, Courjon D. A versatile and stable device allowing the efficient generation of beams with radial, azimuthal or hybrid polarizations[J]. Optics Communications, 252, 12-21(2005). http://www.sciencedirect.com/science/article/pii/S0030401805003044

[20] Ramachandran S, Kristensen P. Optical vortices in fiber[J]. Nanophotonics, 2, 455-474(2013).

[21] Yue Y, Yan Y, Ahmed N et al. Mode properties and propagation effects of optical orbital angular momentum (OAM) modes in a ring fiber[J]. IEEE Photonics Journal, 4, 535-543(2012). http://www.opticsinfobase.org/abstract.cfm?uri=OFC-2012-OM2D.2

[22] Bozinovic N, Golowich S, Kristensen P et al. Control of orbital angular momentum of light with optical fibers[J]. Optics Letters, 37, 2451-2453(2012). http://europepmc.org/abstract/MED/22743418

[23] Ramachandran S, Kristensen P, Yan M F. Generation and propagation of radially polarized beams in optical fibers[J]. Optics Letters, 34, 2525-2527(2009). http://www.opticsinfobase.org/abstract.cfm?URI=ol-34-16-2525

[24] Tsao C Y H, Payne D N, Gambling W A. Modal characteristics of three-layered optical fiber waveguides: A modified approach[J]. Journal of the Optical Society of America A, 6, 555-563(1989). http://www.opticsinfobase.org/abstract.cfm?id=3394

[25] Yan Y, Yue Y, Huang H et al. Efficient generation and multiplexing of optical orbital angular momentum modes in a ring fiber by using multiple coherent inputs[J]. Optics Letters, 37, 3645-3647(2012). http://europepmc.org/abstract/med/22940977

[26] Anderson M E. Measuring vortex charge with a triangular aperture[J]. Optics Letters, 36, 787-789(2011). http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=5950937

[27] Brandão P A, Cavalcanti S B. Topological charge identification of partially coherent light diffracted by a triangular aperture[J]. Physics Letters A, 380, 4013-4017(2016). http://www.researchgate.net/publication/309196942_Topological_charge_identification_of_partially_coherent_light_diffracted_by_a_triangular_aperture