Simple air-gap fiber Fabry–Perot interferometers based on a fiber endface with Sn-microsphere overlay

Design and Implementation of a Novel Measuring Scheme for Fiber Interferometer Based Sensors

“…For example, optical interference signals do not travel in free space and are not affected by the weather and electromagnetic waves. In the literature, the development of all-fiber interferometers with different configurations has yielded considerable results, such as fiber-optic Michelson interferometers (FMI) [1,2,3,4], fiber-optic Mach–Zehnder interferometers (FMZI) [5,6,7,8], fiber-optic Fabry–Perot interferometers (FFPI) [9,10,11,12,13,14,15,16,17], and fiber-optic Fizeau interferometers (FFI) [18,19]. Typical FI based sensing systems and application examples have been categorized into 13 types, according to the measured parameters, i.e., temperature [20,21], mechanical vibration [22,23], acoustic wave [22,24], ultrasound [25,26], voltage [27,28], magnetic field [29,30], pressure [20,31], strain [21,32], flow velocity [33,34], humidity [35,36], gas [37,38], liquid level [39,40], and the refractive index (RI) [41,42].…”

Dynamic micro-air-bubble drifted in a liquid core fiber Fabry-Pérot interferometer for directional fiber-optic level meter

“…Thus, in this study, we proposed a dynamic, miniature, and directional fiber-optic level meter based on a micro-air-bubble drifted in a liquid core fiber Fabry-P erot interferometer (LC-FFPI). Many well known FFPIs have been proposed and widely applied on many physical parametric sensing, 1-7 e.g., external refractive index (RI), 1,7 strain, [2][3][4] and ambient temperature (T) 1,5,6 measurements to investigate the sensitive and practical of the FFPIs. Among the above studies, a new structure of air-gap FFPIs with ellipsoidal or spherical cavity with air bubble (gap) types by special fusion splicing techniques have been reported and also shows the new characteristics and good performances on the optical Fabry-P erot (F-P) interference.…”