Ultralong-Period Microfiber Grating for Simultaneous Measurement of Displacement and Temperature

A structure-modulated ultralong-period microfiber grating (SULPMG) was successfully designed for simultaneous measurement of microdisplacement and temperature. The SULPMG was fabricated based on the standard single-mode fiber using the arc discharge method followed by hydrogenoxygen flame drawing technology. The resonance wavelength of the two notches shifts toward a shorter range when the microdisplacement varies from 0 μm to 65 μm. The results show that the wavelength sensitivity could reach a maximum value of -288.9 pm/μm with a total depth change of 2.95 dB and a high resolution of 69 nm. The temperature sensitivity of the proposed sensor could reach approximately -26.4 pm/°C over an ambient temperature range of 22-90 °C. The proposed sensor can be expected to be applied in fields pertaining to microfabrication and many industrial applications.