提出了一种基于并联结构的多模式复用器/解复用器。该多模式复用器/解复用器由一根少模光纤和两根单模光纤构成。根据有效折射率匹配原则确定了光纤参数,仿真分析了不同芯间距对多模式复用器/解复用器性能的影响,得出最佳芯间距。仿真分析了该多模式复用器/解复用器对应的工作波长带宽。结果表明:该多模式复用器/解复用器不需要结合模式转换器即可实现LP₀₁、LP₁₁和LP₀₂三种模式的复用,最佳耦合区长度为4530 μm,工作波长带宽可达60 nm。

We design a multi-mode multiplexer/de-multiplexer based on parallel mode couplers. The multi-mode multiplexer/de-multiplexer consists of two single mode fibers and a few-mode fiber. According to the effective refractive index matching principle, the parameters of fiber are determined. The influence of different core distances on the performance of multi-mode multiplexer/de-multiplexer is analyzed, and the optimum core distance is determined. The working wavelength bandwidth corresponding to the multi-mode multiplexer/de-multiplexer is analyzed. Simulation results show that the multi-mode multiplexer/de-multiplexer can achieve the multiplexing of LP01, LP11 and LP02 modes without the need of a mode converter, the optimal coupling length is 4530 μm, and the wavelength bandwidth is 60 nm.