Haiyang Xie

Refractive index insensitive temperature sensor based on specialty triple-clad fiber

A refractive index (RI) insensitive temperature sensor based on specialty triple-clad fiber (STCF) is proposed. Based on coupling mode theory, the STCF can be equivalent to a rod waveguide and two tube waveguides. Then the cladding mode resonance characteristic of STCF is analyzed by calculating different mode dispersion curves, which indicates that it works only on the mode resonance from core to the fluorine-doped silica cladding, and finally a resonance wavelength can be obtained. Two straightforward experiments are performed to prove its sensing properties. Experimental results show that it has sensitivities of 72.17 pm/°C at temperature range from 35°C~95°C with characteristics of insensitive to external RI in the range from 1.3450 to 1.4607. Thus, this proposed sensor can be used for solution temperature monitoring in real time.

A few mode fiber curvature sensor based on two spherical-shape structures modal interferometer

In order to improve the equilibrium between fiber sensor performance and cost, a curvature sensor based on Few Mode Fiber(FMF) is proposed. A length of FMF is spliced with waist enlarge between two Single mode Fibers(SMFs) to form two spherical- shape structure. Fiber core mode interfere with clad mode due to the excite and couple function of spherical-shape structure, respectively. The phase difference between the cladding and core regions of the fiber changes with the external strain increase, and then the interference spectrum changes. Two sensors with different length of FMF are fabricated, and the transmission spectrum are obtained. The result shows the optical power at certain wavelength is increasing with the curvature increasing. When the curvature range is 0~0.42m-1 and the FMF is 5.7cm, the curvature sensitivity can be 11.22dB/m-1. When the FMF is 5.9cm, the curvature sensitivity can be climbed to 14.08dB/m-1.

Refractive index insensitive curvature sensor based on cladding-mode resonance of specialty triple-clad fiber

A refractive index insensitive curvature sensor based on cladding-mode resonance of specialty triple-clad fiber (STCF) is proposed. The corresponding mode properties of STCF are investigated theoretically based on the coupled mode theory. The different mode dispersion curves are calculated and a resonance wavelength is obtained. A straightforward experiment is performed to prove the curvature sensitivity. Experimental results shows that the curvature sensitivity can be achieve -11.03374nm/m-1 in the range of 0~1.17m-1, and it also has good linearity. This curvature sensor has the advantages of simple structure, easy manufacturing, highly sensitivity and has no cross-sensitivity when it compared to the other sensors. Thus it can be used for curvature monitoring in time.

Fiber-optic temperature sensor based on specialty triple-clad fiber

A fiber-optic temperature sensor based on specialty triple-clad fiber (STCF) is proposed. Based on coupling mode theory, the STCF can be equivalent to a rod waveguide and two tube waveguides. The different mode dispersion curves are calculated and a resonance wavelength is obtained. A straightforward experiment is performed to prove the temperature sensitivity. Experimental results shows that the temperature sensitivity can be achieve 97.2pm /°C in 20~90°C and there is a good repeatability. The resonance wavelength has a red shift and increase as increasing temperature. Thus, this sensor can be used for temperature monitoring in time.