Two Dimensional Fiber Laser Doppler Velocimeter By Integrated Optical Frequency Shifter

We developed a novel fiber laser Doppler velocimeter (FLDV) using an integrated optical frequency shifter on LiNbO3 substrate. The FLDV system consists of a small probe-head ( diameter of 17 mm and length of 60 mm) with two polarization maintaining fibers for projection and one single mode fiber for detection. The FLDV system can measure the line velocity of two-dimensional vectorial now by only one probe tilted against the direction of the flow. We will describe the construction of the measurement system and the measurements of actual velocities. Two vectorial components of the line velocity were obtained from the calculations between the interference signals detected on a photo-detector.