Abstract:An integrated interferometric fiber optic velocimetry sensor has been proposed and demon.strated at the central wavelength of 638 nm. The sensor is based on the principle of two laser-beamsinterference. The light signal scattered from the particles or vapor is demodulated to measure thewater surface velocity and water vapor velocity. Three velocity measurement experiments are carriedout to measure the velociy, and the experimental data shows that the velocity increases linearly inthe range of 4 mms-' to 100 mms-1, with a slope of linear fitting curve of 0.99777 and the R-Squareof 1.00000. The velocity calculated from frequency shift fits well with the reference velocity. Themaximum average relative error in the three velocity measurements is less than 2.5%. In additionthe maximum speed of 4.398 ms-l is confirmed in the rotating disk calibration experiment, whichexpands the sensor's velocity measurement range. To solve the problem that it is difficult to directlymeasure the velocity of small-scale water surface flow velocity, especially from the aspect of the lowvelocity of air-water surface, the interferometric fiber optic sensor can be applied to the measurementof water surface velocity and wind velocity on the water surface.