We present a new experimental technique for measurement of the refractive index of a photonic crystal fiber (PCF) fundamental mode. We demonstrate that the phase refractive index of the PCF mode can be estimated by analyzing a phase shift of interfering adjacent longitudinal laser modes of a continuous-wave laser corresponding to a shift from constructive to destructive interference. The experimental results are in very good agreement with numerically simulated phase refractive index values.

中文翻译：

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光子晶体光纤模式的相折射率的测量

我们提出了一种新的实验技术，用于测量光子晶体光纤（PCF）基本模式的折射率。我们证明，可以通过分析连续波激光器的相邻相邻纵向激光模式的相移（对应于从相长干涉到相消干涉的偏移）来估计PCF模式的相折射率。实验结果与数值模拟的相折射率值非常吻合。