A High-Precision Wind Speed Sensor Using Modulated Pump Light Dynamic Temperature Response

Abstract

A high-precision wind speed sensor is designed and experimentally verified in this article. Using modulated pump light to heat the cobalt-doped fiber results in a dynamic temperature response in the wind speed sensor. Wind speeds are related to the amplitudes of the dynamic temperature response rather than the static steady-state temperature, which enhances measurement precision. The response sensitivity is higher under lower wind speeds. The temperature of the cobalt-doped fiber rises as it absorbs the pump light energy and then drops when the pump light is turned off. The center wavelength of the fiber Bragg grating (FBG) exhibits periodic shifts with temperature variations. A part of the sensor’s heat is taken away in a wind field, which causes various temperature response amplitudes under the same pump light energy. The amplitudes of the FBG center wavelength vary with different wind speeds. By using the edge-filtering intensity demodulation method, the wavelength variation amplitudes with temperature are converted into the amplitudes of the photodetector’s output voltage variation. The specific relationship between the amplitudes of voltage variation and wind speeds is used to measure wind speed. Measurements were taken within a wind speed range of 0–3 m/s. Experimental results demonstrate that the sensor has good repeatability and stability. Its sensitivity can reach −9.79 mV/(m $\cdot $ s $^{-{1}}$ ) at low wind speeds. The error stays below 0.03 m/s within the range of 0–0.5 m/s.