Two-dimensional directional fiver-optic laser Doppler anemometer based on heterodyning by means of a chirp frequency modulated Nd: YAG miniature ring laser

Abstract A novel method for directional multicomponent laser Doppler anomometry, based on the generation of different carrier frequencies, one for each velocity component, is presented. The laser frequency modulation in conjunction with fiber delay lines of different lengths generates the carrier frequencies without involving additional frequency shift elements, so that a simplified laser Doppler anemometer can be realized.