Light Source Heated Optical Fiber Thermal Anemometer

A highly sensitive optical fiber anemometer is demonstrated by using a polymer Fabry-Perot interferometer (FPI) fabricated on the tip of a single-mode fiber. The polymer FPI absorbs light injected by the broadband light source and generates heat. Its temperature is therefore increased to a certain value which is higher than that of the environment. When airflow is applied, its temperature is reduced and the interference spectrum shifts correspondingly because of the airflow induced cooling effect and wind force. Airflow velocity is therefore measurable by detecting wavelength shift of the optical fiber anemometer. High sensitivity up to −3.13nm /(m/s) is achieved and the response time is ~250 ms.