[1] Croft T, Ritter J, Bhagavatula V. Low-loss dispersion-shifted single-mode fiber manufactured by the OVD process[J]. Journal of Lightwave Technology, 1985, 3(5):931-934.
[2] Yokota H, Kanamori H, Ishiguro Y, et al. Ultra-low-loss pure-silica-core single-mode fiber and transmission experiment[C]//Proceedings of the Optical Fiber Communication Conference,1986:PD3.
[3] Gloge D. Optical fibers for communication[J]. Applied Optics, 1974, 13(2):249-254.
[4] Favre F, Guen D L. High frequency stability of laser diode for heterodyne communication systems[J]. Electronics Letters, 1980, 16(18):709-710.
[5] Essiambre R J, Tkach R W. Capacity trends and limits of optical communication networks[J]. Proceedings of the IEEE, 2012, 100(5):1035-1055.
[6] Qian D, Huang M F, Ip E, et al. High capacity/spectral efficiency 101.7-Tb/s WDM transmission using PDM-128QAM-OFDM over 165-km SSMF within C- and L-bands[J]. Journal of Lightwave Technology, 2012, 30(10):1540-1548.
[7] Mitra P P, Stark J B. Nonlinear limits to the information capacity of optical fibre communications[J]. Nature, 2001, 411(6841):1027-1030.
[8] Tkach R W. Scaling optical communications for the next decade and beyond[J]. Bell Labs Technical Journal, 2010, 14(4):3-9.
[9] Born M, Emil W. Principles of optics:electromagnetic theory of propagation, interference and diffraction of light[J]. CUP Archive, 2000.
[10] Gnauck A H, Winzer P J. Optical phase-shift-keyed transmission[J]. Journal of Lightwave Technology, 2005, 23(1):115.
[11] Kikuchi N, Sasaki S. Highly sensitive optical multilevel transmission of arbitrary quadratureamplitude modulation (QAM) signals with direct detection[J]. Journal of Lightwave Technology, 2010, 28(1):123-130.
[12] Sano A, Masuda H, Kobayashi T, et al. Ultra-high capacity WDM transmission using spectrally-efficient PDM 16-QAM modulation and C-and extended L-band wideband optical amplification[J]. Journal of Lightwave Technology, 2011, 29(4):578-586.
[13] Beppu S, Kasai K, Yoshida M, et al. 2048 QAM (66 Gbit/s) single-carrier coherent optical transmission over 150 km with a potential SE of 15.3 bit/s/Hz[J]. Optics Express, 2015, 23(4):4960-4969.
[14] Richardson D J, Fini J M, Nelson L E. Space-division multiplexing in optical fibres[J]. Nature Photonics, 2013, 7(5):354-362.
[15] Mizuno T, Takara H, Sano A, et al. Dense space-division multiplexed transmission systems using multi-core and multi-mode fiber[J]. Journal of Lightwave Technology, 2016, 34(2):582-592.
[16] Zhu B, Taunay T F, Fishteyn M, et al. 112-Tb/s space-division multiplexed DWDM transmission with aggregate spectral efficiency over a 76.8-km seven-core fiber[J]. Optics Express, 2011, 19(17):16665-16671.
[17] Iano S, Sato T, Sentsui S, et al. Multicore optical fiber[C]//Proceedings of the Optical Fiber Communications Conference and Exhibition, 1979:WB1.
[18] Van Uden R, Correa R A, Lopez E A, et al. Ultra-high-density spatial division multiplexing with a few-mode multicore fibre[J]. Nature Photonics, 2014, 8(11):865-870.
[19] Liu J, Li S, Zhu L, et al. Demonstration of few mode fiber transmission link seeded by a silicon photonic integrated optical vortex emitter[C]//Proceedings of the European Conference on Optical Communication. 2015:1-3.
[20] Ndagano B, Brüning R, Mclaren M, et al. Fiber propagation of vector modes[J]. Optics Express, 2015, 23(13):17330-17336.
[21] Liu J, Li S, Zhu L, et al. Direct fiber vector eigenmode multiplexing transmission seeded by integrated optical vortex emitters[J]. Light:Science and Applications, 2018, 7(3):17148.
[22] Padgett M J. Orbital angular momentum 25 years on[J]. Optics Express, 2017, 25(10):11265-11274.
[23] Wang J, Yang J Y, Fazal I M, et al. Terabit free-space data transmission employing orbital angular momentum multiplexing[J]. Nature Photonics, 2012, 6(7):488-496.
[24] Wang J. Advances in communications using optical vortices[J]. Photonics Research, 2016, 4:B14-B28.
[25] Allen L, Beijersbergen M W, Spreeuw R J C, et al. Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes[J]. Physical Review A, 1992, 45(11):8185-8189.
[26] Bozinovic N, Kristensen P, Ramachandran S. Long-range fiber-transmission of photons with orbital angular momentum[C]//Proceedings of the CLEO:Science and Innovations, 2011:CTuB1.
[27] Ramachandran S, Kristensen P, Yan M F. Generation and propagation of radially polarized beams in optical fibers[J]. Optics Letters, 2009, 34(16):2525-2527.
[28] Bozinovic N, Yue Y, Ren Y, et al. Terabit-scale orbital angular momentum mode division multiplexing in fibers[J]. Science, 2013, 340(6140):1545-1548.
[29] Ingerslev K, Gregg P, Galili M, et al. 12 Mode, MIMO-free OAM transmission[C]//Proceedings of the Optical Fiber Communications Conference and Exhibition, 2017:M2D. 1.
[30] Brunet C, Vaity P, Messaddeq Y, et al. Design, fabrication and validation of an OAM fiber supporting 36 states[J]. Optics Express, 2014, 22(21):26117-26127.
[31] Gregg P, Kristensen P, Golowich S, et al. Stable transmission of 12 OAM states in air-core fiber[C]//Proceedings of the CLEO:Science and Innovations, 2013:CTu2K. 2.
[32] Gregg P, Kristensen P, Ramachandran S. 13.4 km OAM state propagation by recirculating fiber loop[J]. Optics Express, 2016, 24(17):18938-18947.
[33] Ung B, Vaity P, Wang L, et al. Few-mode fiber with inverse-parabolic graded-index profile for transmission of OAM-carrying modes[J]. Optics Express, 2014, 22(15):18044-18055.
[34] Zhang J, Wen Y, Tan H, et al. 80-channel WDM-MDM transmission over 50-km ring-core fiber using a compact OAM DEMUX and modular 4×4 MIMO equalization[C]//Proceedings of the Optical Fiber Communication Conference, 2019:W3F.3.
[35] Zhu L, Zhu G, Wang A, et al. 18 km low-crosstalk OAM+WDM transmission with 224 individual channels enabled by a ring-core fiber with large high-order mode group separation[J]. Optics Letters, 2018, 43(8):1890-1893.
[36] Zhu G, Hu Z, Wu X, et al. Scalable mode division multiplexed transmission over a 10-km ring-core fiber using high-order orbital angular momentum modes[J]. Optics Express, 2018, 26(2):594-604.
[37] Xi X M, Wong G K L, Frosz M H, et al. Orbital-angular-momentum-preserving helical Bloch modes in twisted photonic crystal fiber[J]. Optica, 2014, 1(3):165-169.
[38] TandjÈ A, Yammine J, Dossou M, et al. Ring-core photonic crystal fiber for propagation of OAM modes[J]. Optics Letters, 2019, 44(7):1611-1614.
[39] Tu J, Liu Z, Gao S, et al. Ring-core fiber with negative curvature structure supporting orbital angular momentum modes[J]. Optics Express, 2019, 27(15):20358-20372.
[40] Li S, Wang J. Multi-orbital-angular-momentum multi-ring fiber for high-density space-division multiplexing[J]. IEEE Photonics Journal, 2013, 5(5):7101007.
[41] 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, 2014, 4:3853.
[42] Li S, Wang J. Supermode fiber for orbital angular momentum (OAM) transmission[J]. Optics Express, 2015, 23(14):18736-18745.
[43] 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, 2012, 4(2):535-543.
[44] Wang A, Zhu L, Liu J, et al. Demonstration of hybrid orbital angular momentum multiplexing and time-division multiplexing passive optical network[J]. Optics Express, 2015, 23:29457-29466.
[45] Wang A, Zhu L, Chen S, et al. Characterization of LDPC-coded orbital angular momentum modes transmission and multiplexing over a 50-km fiber[J]. Optics Express, 2016, 24(11):11716-11726.
[46] Liu J, Li S M, Du J, et al. Performance evaluation of analog signal transmission in an integrated optical vortex emitter to 3.6-km few-mode fiber system[J]. Optics Letters, 2016, 41:1969-1972.
[47] Carpenter J A, Thomsen B C, Wilkinson T D. Optical vortex based mode division multiplexing over graded-index multimode fibre[C]//Proceedings of the Optical Fiber Communications Conference and Exhibition, 2013:OTh4G.3.
[48] Chen S, Liu J, Zhao Y, et al. Full-duplex bidirectional data transmission link using twisted lights multiplexing over 1.1-km orbital angular momentum fiber[J]. Scientific Reports, 2016, 6:38181.
[49] Zhu L, Yang C, Xie D, et al. Demonstration of km-scale orbital angular momentum multiplexing transmission using 4-level pulse-amplitude modulation signals[J]. Optics Letters, 2017, 42:763-766.
[50] Liu J, Zhu L, Wang A, et al. All-fiber pre- and post-data exchange in km-scale fiber-based twisted lights multiplexing[J]. Optics Letters, 2016, 41:3896.
[51] Liu J, Li S, Ding Y, et al. Orbital angular momentum modes emission from a silicon photonic integrated device for km-scale data-carrying fiber transmission[J]. Optics Express, 2018, 26(12):15471-15479.
[52] Zhu L, Wang A, Chen S, et al. Orbital angular momentum mode multiplexed transmission in heterogeneous few-mode and multi-mode fiber network[J]. Optics Letters, 2018, 43:1894-1897.
[53] Zhu L, Wang A, Chen S, et al. Orbital angular momentum mode groups multiplexing transmission over 2.6-km conventional multi-mode fiber[J]. Optics Express, 2017, 25:25637-25645.
[54] Wang A, Zhu L, Wang L, et al. Directly using 8.8-km conventional multi-mode fiber for 6-mode orbital angular momentum multiplexing transmission[J]. Optics Express, 2018, 26:10038-10047.
[55] Wang J. Data information transfer using complex optical fields:a review and perspective[J]. Chinese Optics Letters, 2017, 15:030005.
[56] Wang J. Twisted optical communications using orbital angular momentum[J]. Science China Physics, Mechanics & Astronomy, 2019, 62(3):034201.
[57] Van Weerdenburg J J A, Velazquez B A M, van Uden R G H, et al. 10 spatial mode transmission over 40 km 50μm core diameter multimode fiber[C]//Proceedings of the Optical Fiber Communication Conference, 2016:Th4C.3.
[58] Wittek S, Ryf R, Fontaine N K, et al. Mode-multiplexed transmission within and across mode groups of a multimode-fiber[C]//Proceedings of the Optical Fiber Communication Conference, 2019:M2I.2.
[59] Ryf R, Fontaine N K, Chen H, et al. Mode-multiplexed transmission over conventional graded-index multimode fibers[J]. Optics Express, 2015, 23(1):235-246.
[60] Berdagué S, Facq P. Mode division multiplexing in optical fibers[J]. Applied Optics, 1982, 21(11):1950-1955.
[61] Stuart H R. Dispersive multiplexing in multimode optical fiber[J]. Science, 2000, 289(5477):281-283.
[62] Ryf R, Fontaine N K, Wittek S, et al. High-spectral-efficiency mode-multiplexed transmission over graded-index multimode fiber[C]//Proceedings of the European Conference on Optical Communication, 2018:Th3B.1.
[63] Okamoto K. Fundamentals of optical waveguides[M]. New York:Academic Press, 2010.
[64] Kogelnik H, Winzer P. Modal birefringence in weakly guiding fibers[J]. Journal of Lightwave Technology, 2012, 30(14):2240-2245.
[65] Han Y, Li G. Coherent optical communication using polarization multiple-input-multipleoutput[J]. Optics Express, 2005, 13(19):7527-7534.
[66] Savory S J. Digital filters for coherent optical receivers[J]. Optics Express, 2008, 16(2):804-817.
[67] Savory S J. Digital coherent optical receivers:algorithms and subsystems[J]. IEEE Journal of Selected Topics in Quantum Electronics, 2010, 16(5):1164-1179.
[68] Savory S J, Gavioli G, Killey R I, et al. Electronic compensation of chromatic dispersion using a digital coherent receiver[J]. Optics Express, 2007, 15(5):2120-2126.
[69] Beth R A. Mechanical detection and measurement of the angular momentum of light[J]. Physical Review, 1936, 50(2):115-123.
[70] Chen S, Wang J. Characterization of red/green/blue orbital angular momentum modes in conventional G.652 fiber[J]. IEEE Journal of Quantum Electronics, 2017, 53:7200308.
[71] Chen S, Wang J. Theoretical analyses on orbital angular momentum modes in conventional graded-index multimode fibre[J]. Scientific Reports, 2017, 7:3990.
[72] Wang J, Zhu L, Wang A, et al. Demonstration of hybrid orbital angular momentum (OAM) and Gaussian mode encoding/decoding for 10-Gbit/s data transmission through a 2.6-km conventional graded-index multimode (OM3) fiber[C]//Proceedings of the CLEO:Science and Innovations, 2017:SW4I. 1.