Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
Opt Lett. 2013 May 1;38(9):1527-9. doi: 10.1364/OL.38.001527.
Ring microcavities were formed by wrapping ZnS microbelts, which act as the waveguide and gain region of the microcavities on the surface of optical fibers. The ring microcavities with the formation of whispering gallery modes have lasing threshold lower (Q-factor higher) than that of the ZnS microbelts. The excitation of TM modes could also be suppressed by the ring geometries of ZnS microbelts. Furthermore, directional single-mode lasing was realized from a coupled asymmetric ring microcavity. The Vernier coupling effect and deformed geometry of the asymmetric ring microcavity were contributed to the stable single-mode operation and directional emission, respectively.
环形微腔通过在光纤表面包裹作为微腔波导和增益区的 ZnS 微带而形成。形成 whispering gallery 模式的环形微腔的激射阈值比 ZnS 微带低（Q 因子高）。环形 ZnS 微带的几何形状还可以抑制 TM 模式的激发。此外，从耦合非对称环形微腔中实现了定向单模激射。游标耦合效应和非对称环形微腔的变形几何形状分别有助于稳定的单模操作和定向发射。
