Li Hui-Dong, Fu Hai-Wei, Shao Min, Zhao Na, Qiao Xue-Guang, Liu Ying-Gang, Li Yan, Yan Xu. In-fiber Mach-Zehnder interferometer based on fiber core etched air-bubble and core diameter mismatch for liquid refractive index sensingJ. Acta Physica Sinica, 2013, 62(21): 214209. DOI: 10.7498/aps.62.214209