Hybrid AG-FFPI/RLPFG for Simultaneously Sensing Refractive Index and Temperature

Ultrasensitive microtaper with an air-gap microcavity fiber Fabry-Pérot interferometer

“…The works of various all-fiber sensors that incorporate with fiber Fabry-Pérot interferometers for some sensing purposes have focused on enhancing measurement sensitivity and achieving multiple sensing capabilities. The configurations involved the air gap fiber Fabry-Perot interferometers (AG-FFPIs) and the in-line LPFGs for obtaining multiple sensing capabilities and flexibilities have been presented [5][6]. For the above reasons, we can estimate the new configuration proposed in this paper, a micro-tapered fiber combined with an in-line AG-FFPI can achieve new and sensitive characteristics.…”

In-Line Fiber Optic Interferometric Sensors in Single-Mode Fibers

“…However, for these intrinsic FPIs, there still exist the disadvantages of requiring expensive equipment for the cavity fabrication or needing special fibers or using dangerous chemical reagents. In particular, the LPFGs are well known to be sensitive to the ambient variations, and simultaneous measurement of RI and temperature could be realized by cascading the LPFG and the intrinsic or extrinsic FPI [ 36 , 37 ]. Moreover, the definition of the intrinsic and extrinsic FPI becomes vague owing to the advent of specialty fibers and fiber devices.…”

High-Performance Ultrafast Humidity Sensor Based on Microknot Resonator-Assisted Mach–Zehnder for Monitoring Human Breath

“…Fiber-optic sensors have attracted considerable interest in their unique advantages such as corrosion-free, miniaturization, lightweight, and anti-electromagnetic interference. A variety of fiber-optic sensors have been reported for measuring the temperature, − humidity, − refractive index, − and physical and chemical properties. − Among them, optical fiber humidity sensors are essential for environmental monitoring and are extensively used in food processing, air conditioning, electronic product, and medical diagnostics, including human breath monitoring. Human breath has a critical role in the noninvasive diagnosis of diseases, both in hospital and at home .…”