Phased diode arrays for velocity measurements and signal processing

The features and advantages of the use of phased diode arrays for velocity measurement and signal processing are examined. The test setup is described, and the processing of laser array velocimeter signals is discussed. It is demonstrated that because of the strong directional sensitivity, high output power, and compact dimensions of the laser diode arrays, high-speed applications in backscatter modes are particularly advantageous. Improved accuracy is obtained by selected optical devices and off-axis light-collecting methods. To decrease directional sensitivity for turbulent flow, cylindrical lenses can be used. To obtain velocity vectors with more than one component, pulsing methods that also increase the output power of the diodes can be introduced