We experimentally investigate the resonant response in a microsphere coupled with a biconical microfiber coupler (MFC) composed of single- and/or few-mode fibers. The evolution between Lorentz and Fano resonances dependent on the phase difference of the supermodes is demonstrated along the coupling region of the MFC. A flexible narrow-linewidth add-drop filter can be simultaneously achieved with the advantage of easy alignment and efficiently evanescent coupling. In addition, the mode conversion process of the microsphere is demonstrated, and the purity of the ${\mathrm{LP}}_{11}$ mode in a coupler at the whispering gallery mode resonance is analyzed. The proposed MFC coupling system holds great promising applications in optical filtering and sensing, mode switching, and micro-resonator-based combs.

中文翻译：

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与微纤维耦合器耦合的微球的共振响应和模式转换

我们实验研究微球中的谐振响应，该微球与由单模和/或少模光纤组成的双锥微纤维耦合器（MFC）耦合。沿MFC的耦合区域证明了取决于超模的相位差的Lorentz和Fano共振之间的演化。可以同时实现灵活的窄线宽分插滤波器，其优点是易于对准和有效的e逝耦合。此外，还演示了微球的模式转换过程，并给出了其纯度。${\mathrm{LP}}_{11}$分析了耳语画廊模式下耦合器的共振模式。所提出的MFC耦合系统在光学滤波和传感，模式切换以及基于微谐振器的梳子中具有广阔的应用前景。