In this Letter, we demonstrate a whispering-gallery-mode (WGM) microsphere resonator. The device is fabricated by fusion splicing a section of no-core fiber with multimode fiber (MMF) and single-mode fiber at its two ends. The open end of the MMF is etched to create an arc-shaped cavity, with a microsphere glued at its bottom. When the arc of the cavity bottom and microsphere surface are tangent, part of the incident light is coupled into the microsphere and travels exactly one circle before being directed back to the MMF core along the tangent line and exciting the WGM. The device has a $Q$-factor of $1.21\times {10}^4$, and is robust in structure and low in cost.

中文翻译：

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通过在多模光纤末端使用蚀刻腔在微球中进行耳语画廊模式激发

在这封信中，我们演示了耳语画廊模式（WGM）微球共振器。该设备是通过将无芯光纤的一部分与两端的多模光纤（MMF）和单模光纤熔接在一起而制成的。MMF的开口端被蚀刻以形成一个弧形腔，在其底部粘有一个微球。当腔体底部的弧与微球表面相切时，部分入射光会耦合到微球中，并沿正切线直接回到MMF磁芯并激发WGM，从而精确地传播一个圆。该设备有一个$问$的因素 $1.21\times {10}^4$，结构坚固且成本低廉。