Measuring the fluid velocity with the self-mixing speckle of the erbium-doped fiber ring laser

Abstract

The measuring method of the fluid velocity is studied by self-mixing speckle interferometry. A measuring system making up of the ring erbium-doped fiber laser is devised to achieve the information of the fluid velocity. Through Injection- Seeded Erbium-doped fiber ring laser transcendental equation, an equation about the fluid velocity and laser power modulated by self-mixing speckle can be inferred. The relationship between average frequency of the self-mixing speckle signal and the fluid velocity is analyzed, and that how does the average energy spectrum density change with the fluid velocity is studied. In experiments, a suitable signal processing method can be chosen with the grade of the velocity. The experiment is indicated that it is the linear between self-mixing speckle signal and the fluid velocity. The result of the experiments is indicated that self -mixing speckle metrology based on the erbium-doped fiber ring laser can be applied to real time detection of the fluid velocity.