[1] [1] Essiambre R J, Kramer G, Winzer P J, et al. Capacity limits of optical fiber networks[J]. Journal of Lightwave Technology, 2010, 28(4): 662-701.

[2] [2] Li G, Bai N, Zhao N, et al. Space-division multiplexing: The next frontier in optical communication[J]. Advances in Optics and Photonics, 2014, 6(4): 413-487.

[6] [6] Marcuse D. Field deformation and loss caused by curvature of optical fibers[J]. JOSA, 1976, 66(4): 311-320.

[7] [7] Schulze C, Lorenz A, Flamm D, et al. Mode resolved bend loss in few-mode optical fibers[J]. Optics Express, 2013, 21(3): 3170-3181.

[8] [8] Zhao J, Tang M, Oh K, et al. Polarization-maintaining few mode fiber composed of a central circular-hole and an elliptical-ring core[J]. Photonics Research, 2017, 5(3): 261-266.

[9] [9] Zhang Y, Ren F, Fan X, et al. Design of weakly-coupled trench-assisted five-mode M-type fiber for short-haul communication in O band[J]. Optical and Quantum Electronics, 2018, 50: 1-16.

[13] [13] Schermer R T, Cole J H. Improved bend loss formula verified for optical fiber by simulation and experiment[J]. IEEE Journal of Quantum Electronics, 2007, 43(10): 899-909.

[14] [14] Cai M, Shi W, Lou Y, et al. Design and theoretical analysis of broadband bend-resistant low-loss hollow-core anti-resonant fiber[J]. Applied Optics, 2024, 63(21): 5692-5698.