Hot-Wire Anemometer Based on D-Shaped Optical Fiber

Abstract

This article proposes a hot-wire anemometer based on optical fiber embedding an FBG and having a D-shaped transversal section on whose flat surface a thin metallic layer has been deposited. Thanks to this geometrical structure, the optical power flowing through the fiber core can achieve the metallic layer and be converted in heat. The embedded FBG can measure the resulting temperature increase and the temperature fluctuation of the D-fiber caused by the wind flowing. Numerical simulations have been performed in order to select the appropriate design parameters, such as thickness of the metallic layer and its distance from the core. Then, the fabrication process of the device and the experimental results of its characterization in temperature and wind assess its working principle. The developed sensor can work at low power levels of the source and is characterized by small size and high accuracy. Furthermore, it shows high cost-effectiveness and the possibility to modulate its wind sensitivity by setting the source power.