By employing the Langevin equation, we have examined a mode coupling in low and high NA step index plastic optical fibres. The numerical integration of the Langevin equation is based on the computer-simulated Langevin force. The solution matches the experimental data reported previously. We have shown that by solving the Langevin equation (stochastic differential equation) one can treat a mode coupling in multimode low and high NA step index plastic optical fibres, which is the result of fibre's intrinsic random perturbations.

中文翻译：

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使用朗之万方程研究低和高 NA 阶跃折射率塑料光纤中的模式耦合

通过使用朗之万方程，我们研究了低和高 NA 阶跃折射率塑料光纤中的模式耦合。Langevin 方程的数值积分基于计算机模拟的 Langevin 力。该解决方案与之前报告的实验数据相匹配。我们已经表明，通过求解朗之万方程（随机微分方程），可以处理多模低和高 NA 阶跃折射率塑料光纤中的模式耦合，这是光纤固有随机扰动的结果。