We study the Q-factors of whispering gallery modes on the surface of standard optical fibers using both spectral and ring-down measurements and show that annealing by the fire torch yields Q-factors higher than 10 7 . In this case, however, variations of the effective radius are introduced, that make the mode spectrum complicated as a number of modes with a nonzero axial component of the wave vector appear. We demonstrate that tapering the fiber sample allows to evade this complexity and to build up an efficient filter operating in transmission.

中文翻译：

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在锥形光纤表面上采用轴向回音壁模式进行光学滤波

我们使用光谱和振铃测量研究了标准光纤表面上回音壁模式的Q因子，并显示了通过火炬退火产生的Q因子高于10 7。然而，在这种情况下，引入了有效半径的变化，这使得模式频谱变得复杂，因为出现了波矢量的轴向分量非零的多个模式。我们证明了使纤维样品逐渐变细可以避免这种复杂性，并建立起在传输中运行的高效过滤器。