Liu Xin, Cui X L, Wang D N
Opt Lett. 2020 Mar 15;45(6):1467-1470. doi: 10.1364/OL.388166.
An integrated in-fiber coupler is proposed and demonstrated, which can excite whispering-gallery mode (WGM) in a microsphere resonator. This device is fabricated firstly by using femtosecond laser micromachining and a fusing splicing technique to create an inner air cavity with a suspended fiber core, then an open micro-channel is drilled on the top of the inner air cavity, and finally a microsphere is placed inside the air cavity, in contact with the suspended fiber core, to excite the WGM through the evanescent field. In the transmission spectrum of the device, the slopes of the two asymmetric Fano resonance lines of 41.12 dB/nm and $ - {18.46};{\rm dB/nm}$-18.46dB/nm, respectively, and a symmetrical Lorentz line with a quality factor of ${9.32} \times {{10}^3}$9.32×10 can be obtained simultaneously. Such an in-fiber WGM microsphere resonator has the advantages of compact structure, convenient operation, and high durability.
提出并演示了一种集成光纤耦合器，它可以在微球谐振器中激发回音壁模式（WGM）。该器件首先通过飞秒激光微加工和熔接技术制造，以创建一个带有悬浮光纤芯的内部空气腔，然后在内部空气腔顶部钻出一个开放的微通道，最后将一个微球放置在空气腔内，与悬浮光纤芯接触，通过倏逝场激发WGM。在该器件的传输光谱中，可以同时获得两条不对称的法诺共振线，斜率分别为41.12 dB/nm和 - 18.46 dB/nm，以及一条品质因数为9.32×10³ 的对称洛伦兹线。这种光纤内WGM微球谐振器具有结构紧凑、操作方便和耐久性高的优点。
