A cost-efficient fiber-optic strain and temperature sensor has been proposed and demonstrated experimentally. The sensor consists of a segment of polarization-maintaining fiber (PMF) and two segments of multimode fiber (MMF). Two segments of MMF, which are used as beam splitter and combiner, are embedded on both ends of the PMF. The all-fiber sensor is put in the middle of the single-mode fiber. Due to the ratio of the strain and temperature responses of the sensor, the measurement of strain and temperature can be achieved by monitoring the transmission spectrum. The experimental result shows that the strain sensitivity is up to −3.16 pm / μϵ in the range of 0 to 1000 μϵ and the temperature sensitivity is 0.071 nm / ° C in the range from 10°C to 45°C. This sensor exhibits the advantages of low cost and high sensitivity and may have potential application in strain and temperature measurement.
We propose and experimentally demonstrate a compact Mach–Zehnder interferometer (MZI)-based no-core fiber hollow-core fiber no-core fiber (NHN) structure. Two segments of the no-core fiber embedded on two ends of the hollow-core fiber are employed as beam splitter and combiner, which realize an MZI to measure temperature and strain. With the variation of the temperature and strain, the measurement is achieved by monitoring the transmission spectrum shift of the MZI. The results show that the proposed sensor has a temperature sensitivity of 30.92 pm/°C in the range from 30°C to 90°C, and strain sensitivity of 0.652 pm/μϵ in the range from 0 to 700 μϵ, respectively. The NHN structure exhibits the advantages of compactness, easy fabrication, and low cost, which shows the potential sensing applications of the proposed fiber structure.
A hybrid optical fiber structure sensor for simultaneous measurement of temperature and low pressure based on Fabry–Perot (FP) interference and fiber Bragg grating (FBG) is proposed. The FP cavity is fabricated with a capillary pure silica tube, whose one end is surface processed to result in an open FP cavity. The measurement of refractive index change of different pressures has been achieved by monitoring the wavelength shift of the interference pattern in the reflection spectrum. The FP cavity is integrated with the FBG to obtain temperature measurement simultaneously.