Distance, velocity and vibration measurements of fast rotating objects are important tasks. The measurement technique was realized by two superposed fan-shaped interference fringe systems with contrary fringe spacing gradients. The physical principle is based on different wavefront curvatures of four Gaussian beams. The distance is coded in the ratio of the Doppler frequencies of both interference signals.
In order to be able to integrate a sensor into working machines or manufacturing processes, the sensor has to be robust and miniaturized. We present a miniaturized fiber-optic sensor setup of the laser Doppler distance sensor using fiber optic and diffractive optic. Due to the small size of the sensor of only 25x25x60 mm³, also the robustness was increased. Vibration and distance measurements at high speed rotors are presented.