All-fiber rotation speed measurement based on dual-beam speckle interference

An all-fiber rotation speed measurement structure based on dual-beam speckle interference is proposed. A distributed feedback laser as the light source generates two independent laser beams through a coupler and two circulators. Scattered by the object, the two laser beams interfere separately with the light reflected from the ends of the two fibers, which can be used to measure the rotation speed. The experiment results show that the structure can accurately measure the rotation speed of the object, with relative errors less than 0.5%.