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针对少模多芯光纤中存在的纤芯内模式间的耦合及芯间模式耦合等问题, 提出一种阶跃型环形芯组成的7芯结构光纤, 每个纤芯可支持5个模式. 各纤芯具有一个中心低折射率区域和一个高折射率环, 保证纤芯内模式间均具有较大的折射率差, 从而减小模式间耦合问题. 运用有限元法模拟分析了中心纤芯和外纤芯的弯曲损耗、模式间的串扰特性及纤芯参数对串扰性能的影响. 数据模拟结果表明, 当波长为1.55 μm, 这种多芯光纤在弯曲半径为50 mm时, 弯曲损耗远低于光纤衰减损耗, 且纤芯中5个模式的相邻纤芯之间串扰均小于–20 dB/100 km, 因而这种多芯光纤在小弯曲半径下仍可实现纤芯间独立的长距离信息传输.Aiming at solving the problems of coupling between modes in a core and mode coupling between cores in few-mode multi-core fiber, a fiber with seven cores each with step index is proposed, and each core can support five modes. Each core has a central low refractive index region and a high refractive index ring to ensure that there is a large refractive index difference between modes in the core, so as to reduce the problem of mode coupling. The bending loss of central core and outer core, the crosstalk characteristics between modes and the influence of core parameters on crosstalk performance are simulated and analyzed by the finite element method. The simulation results show that at a wavelength of 1.55 μm and a bending radius of 50 mm, the bending loss of the proposed multi-core fiber is much lower than its attenuation loss, and the crosstalk between the adjacent cores of the five core modes are less than –20 dB/100 km. Therefore, this multi-core fiber can realize independent transmission of the core modes with long-distance under small bending radius.
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Keywords:
- few mode multi-core fiber /
- inter-core crosstalk /
- bending loss /
- mode field








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