We consider light pulses in a circular array of $2N$ coupled nonlinear optical waveguides. The waveguides are either Hermitian or alternate gain and loss in a $\mathcal{PT}$-symmetric fashion. Simple patterns in the array include a ring of $2N$ pulses traveling abreast and a breather—a string of pulses where all even and all odd waveguides flash in turn. In addition, the structure displays solitons gyrating around the necklace by switching from one waveguide to the next. Some of the gyrating solitons are stable while other ones are weakly unstable and evolve into gyrating multiflash strings. By tuning the gain-loss coefficient, the gyration of solitons in a non-Hermitian array may be reversed without changing the direction of their translational motion.

中文翻译：

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在光波导项链中旋转孤子

我们考虑光脉冲的圆形阵列 $\mathrm{2个}ñ$耦合的非线性光波导。波导可以是Hermitian波导，也可以是交替的增益和损耗。$\mathcal{PT}$对称的时尚。数组中的简单模式包括一圈$\mathrm{2个}ñ$并排呼吸的脉冲-一连串脉冲，所有偶数和奇数波导依次闪烁。此外，该结构还显示了通过从一个波导切换到另一个波导而绕项链旋转的孤子。一些旋转孤子是稳定的，而另一些则是不稳定的，并演变为旋转多闪弦。通过调整增益损失系数，可以在不改变非Hermitian阵列的平移运动方向的情况下反转其孤子的回转。