The fabrication of an ultra-compact, highly sensitive anemometer on a hundred-micron fiber end face poses a formidable challenge. Traditional thermal anemometers often sacrifice low power consumption and temperature control for enhanced range and sensitivity. To overcome these limitations, we introduce a microtip-based thermal anemometer seamlessly integrated with optical fiber ends. First, a SiO2 microtip was prepared by the discharge melting tapering technique. Subsequently, a polymer microtip doped with photothermal material was further grown on the SiO2 microtip by photoinduced polymerization. This dual-layer microtip structure forms a cascade of Fabry-Pérot interferometer (FPI) and increases the sensitivity by approximately 10.8 times based on vernier effect. Zr-PDI is a metal-organic framework (MOF) with a photothermal efficiency of 52.3%, which can reach 113°C under 1.96mW (808 nm) laser irradiation. Experimental results demonstrate that the sensor achieves the wind speed detection range of 0–20 m/s, with a maximum sensitivity of 7.36 nm/(m/s) in the range of 0–3 m/s. This low-power, ultra-compact sensor features highly sensitive, wide-range wind speed measurement capabilities.

A thin-diameter photonic crystal fiber (TDPCF) magnetic field sensor based on hole collapse and infiltration is proposed and demonstrated. Due to the controlled hole collapse in TDPCF, the interaction between the mode field distribution and the magnetic fluid (MF) is effectively strengthened, causing the direct absorption and scattering of magnetic nanoparticles to transmitted light. Consequently, the proposed sensor exhibits a magnetic field sensitivity of up to 0.099 dB/Oe within the range of 0 to 60 Oe. The TDPCF-based magnetic field sensor has several desirable merits such as high sensitivity, convenient integration, and good stability, which provides a promising candidate in environmental and industrial-related magnetic field monitoring applications.