[1] T. Čižmár, K. Dholakia. Exploiting multimode waveguides for pure fibre-based imaging. Nat. Commun., 3, 1027(2012).

[2] R. J. Essiambre, R. Ryf, N. K. Fontaine, S. Randel. Breakthroughs in photonics 2012: space-division multiplexing in multimode and multicore fibers for high-capacity optical communication. IEEE Photon. J., 5, 0701307(2013).

[3] N. Bozinovic, Y. Yue, Y. Ren, M. Tur, P. Kristensen, H. Huang, A. E. Willner, S. Ramachandran. Terabit-scale orbital angular momentum mode division multiplexing in fibers. Science, 340, 1545-1548(2013).

[4] J. W. Nicholson, J. M. Fini, A. M. DeSantolo, X. Liu, K. Feder, P. S. Westbrook, V. R. Supradeepa, E. Monberg, F. DiMarcello, R. Ortiz, C. Headley, D. J. DiGiovanni. Scaling the effective area of higher-order-mode erbium-doped fiber amplifiers. Opt. Express, 20, 24575-24584(2012).

[5] S. Ramachandran, J. M. Fini, M. Mermelstein, J. W. Nicholson, S. Ghalmi, M. F. Yan. Ultra-large effective-area, higher-order mode fibers: a new strategy for high-power lasers. Laser Photon. Rev., 2, 429-448(2008).

[6] B. Zwan, S. Legge, J. Holdsworth, B. King. Spatio-spectral analysis of supercontinuum generation in higher order electromagnetic modes of photonic crystal fiber. Opt. Express, 21, 834-839(2013).

[7] Y. Chen, Z. Chen, W. J. Wadsworth, T. A. Birks. Nonlinear optics in the LP₀₂ higher-order mode of a fiber. Opt. Express, 21, 17786-17799(2013).

[8] S. O. Konorov, E. E. Serebrannikov, A. M. Zheltikov, P. Zhou, A. Tarasevitch, D. von der Linde. Mode-controlled colors from microstructure fibers. Opt. Express, 12, 730-735(2004).

[9] L. Rishøj, B. Tai, P. Kristensen, S. Ramachandran. Discovery of soliton self-mode conversion in multimode optical fibers.

[10] L. G. Wright, D. N. Christodoulides, F. W. Wise. Controllable spatiotemporal nonlinear effects in multimode fibres. Nat. Photonics, 9, 306-310(2015).

[11] K. Krupa, A. Tonello, B. M. Shalaby, M. Fabert, A. Barthélémy, G. Millot, S. Wabnitz, V. Couderc. Spatial beam self-cleaning in multimode fibres. Nat. Photonics, 11, 237-241(2017).

[12] M. Schnack, T. Hellwig, K. Fallnich. Ultrafast, all-optical control of modal phases in a few-mode fiber for all-optical switching. Opt. Lett., 41, 5588-5591(2016).

[13] M. Ma, L. R. Chen. Harnessing mode-selective nonlinear optics for on-chip multi-channel all-optical signal processing. APL Photon., 1, 086104(2016).

[14] J. Demas, G. Prabhakar, T. He, S. Ramachandran. Wavelength-agile high-power sources via four-wave mixing in higher-order modes. Opt. Express, 25, 7455-7464(2017).

[15] D. Cruz-Delgado, R. Ramirez-Alarcon, E. Ortiz-Ricardo, J. Monroy-Ruz, F. Dominguez-Serna, H. Cruz-Ramirez, K. Garay-Palmett, A. B. U’Ren. Fiber-based photon-pair source capable of hybrid entanglement in frequency and transverse mode, controllably scalable to higher dimensions. Sci. Rep., 6, 27377(2016).

[16] K. Rottwitt, J. G. Koefoed, E. N. Christensen. Photon-pair sources based on intermodal four-wave mixing in few-mode fibers. Fibers, 6, 32-34(2018).

[17] R. H. Stolen, J. E. Bjorkholm, A. Ashkin. Phase-matched three-wave mixing in silica fiber optical waveguides. Appl. Phys. Lett., 24, 308-310(1974).

[18] R. H. Stolen. Phase-matched-stimulated four-photon mixing in silica-fiber waveguides. IEEE J. Quantum Electron., 11, 100-103(1975).

[19] J. Cheng, M. E. V. Pedersen, K. Charan, K. Wang, C. Xu, L. Grüner-Nielsen, D. Jakobsen. Intermodal four-wave mixing in a higher-order-mode fiber. Appl. Phys. Lett., 101, 161106(2012).

[20] R. Essiambre, M. A. Mestre, R. Ryf, A. H. Gnauck, R. W. Tkach, A. R. Chraplyvy, Y. Sun, X. Jiang, R. Lingle. Experimental investigation of inter-modal four-wave mixing in few-mode fibers. IEEE Photon. Technol. Lett., 25, 539-542(2013).

[21] S. M. M. Friis, I. Begleris, Y. Jung, K. Rottwitt, P. Petropoulos, D. J. Richardson, P. Horak, F. Parmigiani. Inter-modal four-wave mixing study in a two-mode fiber. Opt. Express, 24, 30338-30348(2016).

[22] J. Demas, P. Steinvurzel, B. Tai, L. Rishøj, Y. Chen, S. Ramachandran. Intermodal nonlinear mixing with Bessel beams in optical fiber. Optica, 2, 14-17(2015).

[23] H. Pourbeyram, E. Nazemosadat, A. Mafi. Detailed investigation of intermodal four-wave mixing in SMF-28: blue-red generation from green. Opt. Express, 23, 14487-14500(2015).

[24] C.-S. Bres, A. O. J. Wiberg, B. P.-P. Kuo, N. Alic, S. Radic. Wavelength multicasting of 320-Gb/s channel in self-seeded parametric amplifier. IEEE Photon. Technol. Lett., 21, 1002-1004(2009).

[25] B. Fang, O. Cohen, M. Liscidini, J. E. Sipe, V. O. Lorenz. Fast and highly resolved capture of the joint spectral density of photon pairs. Optica, 1, 281-284(2014).

[26] G. P. Agrawal. Nonlinear Fiber Optics(2005).

[27] J. C. Knight, J. Arriaga, T. A. Birks, A. Ortigosa-Blanch, W. J. Wadsworth, P. St. J. Russell. Anomalous dispersion in a photonic crystal fiber. IEEE Photon. Technol. Lett., 12, 807-809(2000).

[28] D. Nodop, C. Jauregui, D. Schimpf, J. Limpert, A. Tünnermann. Efficient high-power generation of visible and mid-infrared light by degenerate four-wave-mixing in a large-mode-area photonic-crystal fiber. Opt. Lett., 34, 3499-3501(2009).

[29] J. Hansryd, P. A. Andrekson, M. Westlund, J. Li, P. O. Hedekvist. Fiber-based optical parametric amplifiers and their applications. IEEE J. Sel. Top. Quantum Electron., 8, 506-520(2002).

[30] P. Steinvurzel, J. Demas, B. Tai, Y. Chen, L. Yan, S. Ramachandran. Broadband parametric wavelength conversion at 1 μm with large mode area fibers. Opt. Lett., 39, 743-746(2014).

[31] J. Demas, L. Rishøj, S. Ramachandran. Free-space beam shaping for precise control and conversion of modes in optical fiber. Opt. Express, 23, 28531-28545(2015).

[32] J. Demas, G. Prabhakar, T. He, S. Ramachandran. Broadband and Wideband parametric gain via intermodal four-wave mixing in optical fiber. Conference on Lasers and Electro-Optics (CLEO), SM3M.1(2017).

[33] J. Demas, L. Rishøj, X. Liu, G. Prabhakar, S. Ramachandran. High-power, wavelength-tunable NIR all-fiber lasers via intermodal four-wave mixing. Conference on Lasers and Electro-Optics (CLEO), JTh5A.8(2017).