A novel thermal anemometer based on a core offset single-mode fiber (SMF) combined with a fiber Bragg grating (FBG) coated with silver film is proposed. Light from a pump laser at 1450 nm propagating down the fiber is coupled by the offset into the fiber cladding. A silver coating was deposited on the fiber surface over the Bragg grating structure to absorb the light. As a result, the dynamic thermal equilibrium would be reached between the laser heating and air flow cooling by monitoring the FBG's wavelength shift. Experimental results reveal that the Bragg wavelength shift is related to the flow velocity and the highest resolution of the thermal anemometer is about 0.05 m/s in the range of 0-17.31 m/s.

Additional Metadata
Keywords Core offset, Fiber Bragg grating, Optical fiber sensor, Thermal anemometer
Persistent URL dx.doi.org/10.1117/12.970514
Conference 22nd International Conference on Optical Fiber Sensors
Cheng, J. (Jia), Zhou, Y. (Yan), Dong, X. (Xinyong), & Zhou, W. (2012). Fiber-optic thermal anemometer based on metallic coated fiber Bragg grating. Presented at the 22nd International Conference on Optical Fiber Sensors. doi:10.1117/12.970514