Simultaneous strain and temperature sensor based on polarization maintaining fiber and multimode fiber

The impact of polarization‐maintaining and multimode fibre lengths on strain and temperature sensitivities of single‐mode–multimode–polarization‐maintaining–multimode–single‐mode‐based fibre optic sensors

“…Compared with Refs. [11][12][13][14][15]19,[22][23][24], the proposed SMPMS temperature sensor shows a high sensitivity of 2.366 nm/°C. At the same time, compared with the sensing structure of the reference, this structure has the advantages of higher sensitivity, simple manufacture and low cost.…”

A Probe-Shaped Sensor With FBG and Fiber-Tip Bubble for Pressure and Temperature Sensing

“…A variety of optical fiber sensors have been fabricated to gather information of multifarious physical and chemical parameters, such as temperature [1], pressure [2], curvature [3,4], humidity [5], and refractive index (RI) [6]. In order to fabricate these sensors, various kinds of fibers are adopted, such as photonic crystal fiber (PCF) [7,8], polarization-maintaining fiber [9,10], twin-core fiber [11], sapphire optical fiber [12], micro-fiber [13], and D-shaped fiber [14]. The measurement principle of the sensors depends on the devices, such as the fiber Bragg grating (FBG) [15], long period grating [16], tapered fiber [17], Mach-Zehnder interferometer (MZI) [18], Fabry-Perot interferometer (FPI) [19], and Sagnac loop interferometer [20].…”

High Strain Sensitivity Temperature Sensor Based on a Secondary Modulated Tapered Long Period Fiber Grating

“…To address different requirements in various research fields, sensing characteristics have been selected for simultaneous measurement, such as simultaneous measurement of temperature and strain [3]- [5], temperature and refractive index (RI) [6], temperature and torsion [7], temperature and magnetic field [8], liquid level and RI [9], shape and temperature [10], pressure and temperature [11], and others [12]- [14] Simultaneous measurement of strain and temperature is more widely used in some fields than other dual-parameter measurements, including automobiles, spacecraft, nondestructive evaluation of civil infrastructure, and environmental monitoring. Hence, several structures that can realize simultaneous measurement of strain and temperature have been proposed in recent years, including cascade long period fiber grating (LPFG) [15]; cascade fiber Bragg grating [16]; a fiber grating inscribed on a special optical fiber [17], [18]; an LPFG induced by electric-arc discharge [19]; an LPFG cascading another fiber structure, as combined with a tapered three-core fiber [20]; hybrid LPFG/MEFPI sensor [21]; microtapered fiber grating [22]; asymmetrical fiber Mach-Zehnder interferometer [23]; and others [24], [25]. It has been confirmed that these proposed structures can solve the problem of temperature interference during strain measurement, but they have a disadvantage of low strain sensitivity.…”