Hot-wire anemometer using cobalt-doped fiber-based Michelson interferometer

A hot-wire anemometer based on a dual-arm optical fiber Michelson interferometer (MI) including a short length of laser heated cobalt-doped fiber (CDF) is proposed. The CDF is 4.5 mm-long and fusion spliced to the end of the sensing arm. Cooling induced by airflow causes wavelength shift of the MI's interference spectrum. Airflow velocity is therefore measured by detecting wavelength shift of the interference fringe. Experimental results show that the sensitivity at airflow velocity of 0.1 m/s is up to -2.49 nm/(m/s) and the measurement range is 0 to 5.0 m/s. This CDF-based MI anemometer offers advantages of high sensitivity, simple structure, ease of fabrication and low cost.