Hot-wire Anemometer Based on Etched Fiber Bragg Grating Coated with Silver Film

A hot-wire anemometer is proposed based on a cladding-etched optical fiber Bragg grating (FBG) coated with a layer of silver film, which absorbs light from a pump laser via a waist-enlarged optical fiber bitaper to generate heat and hence a relatively high initial temperature of the FBG. Experimental results show that cladding etching of the FBG increases the initial temperature and hence improves the measurement sensitivity and range. High sensitivity up to ~696.3 pm/(m/s) is achieved and the measurement range covers 0~20 m/s.