Refractive Index Sensing Based on Mach-Zehnder InterferometerFormed by Three Cascaded Single-Mode Fiber Tapers

摘要

We report the fabrication of a highly sensitive refractive-index 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. Experimentalresults show that the sensitivity of the device is 0.286 nm for a 0.01 RI change, which is about eleven times higher thanthat of the normal two cascaded tapers MZ interferometer. Such kind of low-cost and highly sensitive fiber-opticrefractive index sensors will find applications in chemical or bio-chemical sensing fields.