Opt Lett. 2018 Jul 15;43(14):3345-3348. doi: 10.1364/OL.43.003345.
We investigate stability of optical solitons in graded-index (GRIN) fibers by solving an effective nonlinear Schrödinger equation that includes spatial self-imaging effects through a length-dependent nonlinear parameter. We show that this equation can be reduced to the standard NLS equation for optical pulses whose dispersion length is much longer than the self-imaging period of the GRIN fiber. Numerical simulations are used to reveal that fundamental GRIN solitons as short as 100 fs can form and remain stable over distances exceeding 1 km. Higher-order solitons can also form, but they propagate stably over shorter distances. We also discuss the impact of third-order dispersion on a GRIN soliton.
我们通过求解一个有效非线性薛定谔方程来研究梯度折射率（GRIN）光纤中光孤子的稳定性，该方程通过与光纤长度相关的非线性参数包含了空间自成像效应。我们表明，对于色散长度远长于 GRIN 光纤自成像周期的光脉冲，该方程可以简化为标准的NLS 方程。数值模拟揭示了，即使是短至 100fs 的基本 GRIN 孤子也可以形成并在超过 1km 的距离上保持稳定。高阶孤子也可以形成，但它们只能在较短的距离上稳定传播。我们还讨论了三阶色散对 GRIN 孤子的影响。
