Strain Sensor Based on Thin Core-Tapered Three Cores-Thin Core Fiber Structure

Fig. 3. Interference spectrum, strain fitting and spatial spectrum. (a) Interference spectra of three-core optical fibers with different lengths; (b) strain fitting diagram of three-core optical fibers with different lengths and tapered waist diameter of 42.60 μm; (c) spatial frequency spectrum diagram of sensor with tapered waist diameter of 41.20 μm

Download full size

Fig. 4. Strain interference spectra of optical fibers with different tapered waist diameters in the same strain range and the linear fitting of wavelength drift caused by strain. (a) 125-μm tapered waist diameter; (b) 42.60-μm tapered waist diameter; (c) 41.90-μm tapered waist diameter; (d) 41.20-μm tapered waist diameter

Download full size

Fig. 5. Schematic diagram of temperature measuring device

Download full size

Fig. 6. Interference spectra of different waist diameters and temperatures. (a) 42.60-μm tapered waist diameter; (b) 41.20-μm tapered waist diameter

Download full size

Table 1. Performance comparison of the different optical fiber strain sensors

View table

Table 1. Performance comparison of the different optical fiber strain sensors

Structure	Strain sensitivity /(pm·με^-1)	Temperature sensitivity /(pm·℃^-1)	Cross sensitivity /(με·℃^-1)	Reference
Long-period fiber grating	30.00	37.00	1.230	Ref. [7]
Photonic crystal fiber	-14.89	-243.8	16.37	Ref. [8]
Four-core fiber	-1.780	209.0	117.4	Ref. [15]
Hollow fiber and fiber Bragg grating	-0.709 and 1.020	24.55 and 12.76	34.63 and 12.51	Ref. [17]
Few-mode fiber and fiber Bragg grating	-2.000 and 0.67	-34.3 and 10.7	17.15 and 15.97	Ref. [26]
TTCF-TTCFs	-3.470	34.52	9.950	This work