The Study On Self-mixing Effect Based On Distributed Bragg Reflective (DBR) Fiber Laser

Since laser is invented, relying on which, optical measuring technique has been used widely. Nowadays, the emergence of measurement method based on laser self-mixing interference effect provides new way for laser optical measurement technique. The basic theory of self-mixing interference effect is utilizing the interference between the light reflected or scattered by external object and the light inside cavity, which modulates some parameters of the laser output like power, frequency, gain and linewidth enhancement factor. Thus, by demodulating the self-mixing interference signal, it can be easy to realize the measurement of many physical quantities carried by the target object, such as vibration, displacement, absolute distance, velocity, speckle, object shape and interior wounds in workpiece. The laser self-mixing interference measuring system has not only a simple structure but also low requirement for laser source, so there are many kinds of lasers that can be used in the system such as semiconductor laser diodes, gas lasers, vertical cavity surface emitting lasers (VCSEL), quantum well lasers and fiber lasers. It should be emphasized that, fiber lasers are focused on its'some special characteristics. In the view of the above, the paper study on the self-mixing interference effect based on Erbium-Ytterbium (Er-Yb) co-doped distributed Bragg reflective (DBR) fiber laser. The article is organized as follows:1. The development history and current situation of self-mixing interference measuring technique is introduced;2. The different types of models of self-mixing effect are summarized;3. The researching advance of fiber-coupled self-mixing interference effect is demonstrated4. The self-mixing interference measuring system based on Er-Yb co-doped fiber laser is discussed. Especially, the feasibility of application of self-mixing interference vibration measuring system with long distance fiber is researched. 5. The theory and experiment researching of self-mixing interference effect based on Er-Yb co-doped DBR fiber laser are presented;6. Summary and prospect forecast.