Realistic multiport interferometers (beamsplitter meshes) are sensitive to component imperfections, and this sensitivity increases with size. Self-configuration techniques can be employed to correct these imperfections, but not all techniques are equal. This paper highlights the importance of algorithmic stability in self-configuration. Naive approaches based on sequentially setting matrix elements are unstable and perform poorly for large meshes, while techniques based on power ratios perform well in all cases, even in the presence of large errors. Based on this insight, we propose a self-configuration scheme for triangular meshes that requires only external detectors and works without prior knowledge of the component imperfections. This scheme extends to the rectangular mesh by adding a single array of detectors along the diagonal.

中文翻译：

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自配置大型多端口干涉仪的稳定性

现实的多端口干涉仪（分束器网格）对元件缺陷很敏感，并且这种敏感性随着尺寸的增加而增加。可以采用自配置技术来纠正这些缺陷，但并非所有技术都是平等的。本文强调了算法稳定性在自配置中的重要性。基于顺序设置矩阵元素的朴素方法不稳定，对于大网格表现不佳，而基于功率比的技术在所有情况下都表现良好，即使存在大错误也是如此。基于这一见解，我们提出了一种三角形网格的自配置方案，该方案只需要外部检测器，并且无需先验了解组件缺陷即可工作。该方案通过沿对角线添加单个探测器阵列扩展到矩形网格。