[1] D Gloge. Weakly guiding fibers. Applied Optics, 10, 2252-2258(1971).

[2] Suying Liao, 廖素英, Mali Gong, 巩马理. New progress of large mode area fibers. Infrared and Laser Engineering, 40, 85-92(2011).

[3] 张大勇, Dayong Zhang, Yuqing Fu, 傅玉青, 冯国英, Guoying Feng. Characteristics of laser modes in step index fiber. Infrared and Laser Engineering, 37, 82-86(2008).

[4] [4] John Crisp. Introduction to Fiber Optics[M]. 2nd ed. London: Biddles Ltd, 2001.

[5] [5] Michael Bass, Eric W, Van Stryl. Fiber Optics Hbook[M]. New Yk: McGrawHill Companies Inc, 2002.

[6] [6] Rongqing Hui, Maurice O’Sullivan. Fiber Optic Measurement Techniques[M]. Burlington: Elsevier Academic Press, 2009.

[7] [7] Fed Mitschke. Fiber Optics Physics Technology[M]. Berlin: SpringerVerlag, 2009.

[8] [8] Jacques Bures. Guided Opitcs Optical Fibers Allfiber Components[M]. Weinheim: WILEYVCH Verlag GmbH & Co. KGA, 2009.

[9] [9] Dietrich Marcuse. They of Dielectric Optical Waveguides[M]. New Yk: Academic Press Inc, 1974.

[10] [10] Rid J Black, Langis Gagon. Optical Wavegude Modes Polarization, Coupling, Symmetry[M]. New Yk: McGrawHill Companies Inc, 2010.

[15] Guobin Ren, 任国斌, Zhi Wang, 王智, 娄淑琴, Shuqin Lou. Study on mode degeneracy in photonic crystal fibers. Acta Phy Sin, 53, 1856(2004).

[16] Lu Peng, Wang Anbo, Soker Shay. Adaptive mode control based on a fiber Bragg grating. Opt Lett, 40, 3488-3491(2015).

[17] Hong Seongjin, Choi Kyoungyeon, Soo Lee Yong. Two-mode fiber with a reduced mode overlap for uncoupled mode-division multiplexing in C+L band. Curr Opt Photon, 2, 233-240(2018).

[18] Schulze Christian, Brüning Robert, Schröter Siegmund. Mode coupling in few-mode fibers induced by mechanical stress. J Lightwave Technol, 33, 4488-4496(2015).

[19] Liangjin Huang, Jinyong Leng, Pu Zhou. Adaptive mode control of a few-mode fiber by real-time mode decomposition. Opt Express, 23, 28082-28090(2015).

[20] E Snitzer, H Osterberg. Observed dielectric waveguide modes in the visible spectrum. Journal of the Optical Society of America, 51, 499-505(1961).

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

[22] [22] Kenji Kawano, Tsutomu Kitoh, Introduction to Optical Waveguide Analysis[M]. New Yk: John Willy & Sons Inc, 2001.

[23] [23] Katsunari Okamoto, Fundamentals of Optical Waveguides[M]. 2nd ed. Ibaraki: Okamoto Labaty Ltd, 2006.