title: Refractive index sensing based on Mach-Zehnder interferometer formed by three cascaded single-mode fiber tapers.
abstract: We report a highly sensitive refractive index (RI) sensor based on three cascaded single-mode fiber tapers, in which a weak taper is sandwiched between the two tapers to improve the sensitivity of the sensor. Experimental results show that the sensitivity of the device is 0.286 nm for a 0.01 RI change, which is about four times higher than that of the normal two-cascaded-taper-based Mach-Zehnder interferometer. In addition, the sensitivity of the device could be enhanced by tapering a longer and thinner middle weak taper. Such kinds of low-cost and highly sensitive fiber-optic RI sensors would find applications in chemical or biochemical sensing fields.
authors.affiliation: Key Laboratory of Optoelectronic Technology and Systems (Ministry of Education), Chongqing University, Chongqing 400044, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Tao
authors.initials: T
authors.lastname: Zhu
authors.forename: Ming
authors.initials: M
authors.lastname: Deng
authors.forename: De-Wen
authors.initials: DW
authors.lastname: Duan
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Shi
authors.forename: Jun
authors.initials: J
authors.lastname: Yao
authors.forename: Yun-Jiang
authors.initials: YJ
authors.lastname: Rao