Fig. 1. Schematic diagram of TS-MSL ultra-high sensitive temperature sensor structure

Fig. 2. Simulation analysis results of optical field transmission of different micro-nano fiber Sagnac rings. (a) Ordinary SMF micro-nano fiber Sagnac ring; (b) TS-MSL

Fig. 3. Simulation results of different coupling lengths

Fig. 4. Comparison between experimental transmission spectrum of TMF and simulated transmission spectrum at 45000 μm

Fig. 5. Comparison of temperature sensitivity simulation results of micro-nano fiber Sagnac rings based on SMF and TMF

Fig. 6. Physical image of TS-MSL (diagram of cone area microscope after packaging PDMS, with insert image showing TMF cross-sectional view of cone area)

Fig. 7. Diagram of experimental setup

Fig. 8. Comparison of interference spectra of normal single-mode micro-nano fiber Sagnac loop under three different cone diameters

Fig. 9. Temperature sensing experiment results of normal SMF micro-nano fiber Sagnac ring. (a) Interference spectra at different temperatures; (b) fitting curve of wavelength-temperature

Fig. 10. Experimental results of TS-MSL temperature sensing. (a) Interference spectra at different temperatures; (b) fitting curve of wavelength-temperature

Fig. 11. Comparison of interference spectra of TS-MSL before and after packaging PDMS

Fig. 12. Temperature sensing experiment results of TS-MSL after adding PDMS package. (a) Interference spectra at different temperatures; (b) fitting curve of wavelength-temperature

Fig. 13. Linear fitting curves of wavelength shifts for temperature rise and fall