Research On Self-mixing Velocity Measurement And Phase Modulation Of Distributed Feedback Fiber Laser

The laser self-mixing interference measurement technology is a novel optical precision measurement technology, which actively utilizes the influence of external optical feedback on the laser output characteristics to measure the motion information carried by the external target. In recent years, with the continuous development of laser technology and signal processing technology, the laser self-mixing interference measurement technology becomes more and more mature, which has been widely applied in industry, military, biomedicine and other fields. The distributed feedback (DFB) fiber laser is a burgeoning fiber grating laser, which has great application prospects in optical communication and sensing fields owing to the advantages of simple structure, narrow linewidth, low phase noise and stable output. In this paper, the DFB fiber laser is introduced in the laser self-mixing interference area and the all-fiber DFB fiber laser self-mixing interference velocity measurement and phase modulation system is studied.The main research works of this paper are as following:1. We introduce the inner structure of DFB fiber laser, and then analysis the working principle of the DFB fiber laser by combining the working principle of the fiber laser and phase shifted grating. Based on the DFB fiber laser working principle and DFB fiber laser amplification equation as well as Boundary condition equation, we analysis and simulate the all-fiber DFB fiber laser self-mixing interference system.2. We establish the theoretical model of the all-fiber DFB fiber laser Doppler velocity measurement system, and the simulations on different velocities are carried. In the experiment, we successfully establish the all-fiber DFB fiber laser self-mixing Doppler velocity measurement system, which can realize velocity measurement in the range of 3.58mm/s to 2216mm/s and the relative error is less than 1%.3. The phase modulation technology is introduced into the laser self-mixing interference system, and the theoretical model of all-fiber DFB fiber laser self-mixing interference phase modulation system is established. Based on the theoretical model, we carried on the simulation. Finally, we successfully establish the all-fiber DFB fiber laser self-mixing interference phase modulation system in the experiment based on the simulated results.The innovations of this paper mainly include:1. The theoretical model of all-fiber DFB fiber laser self-mixing interference system is established, which provides a scientific basis for the DFB fiber laser self-mixing interference measurement technology.2. We successfully construct the all-fiber DFB fiber laser self-mixing Doppler velocity measurement system. The experimental results indicate that this novel all-fiber laser self-mixing velocity measurement system can realize wide-range and high-accuracy velocity measurement. In the experiment, the range of velocity measurement is from 3.58mm/s to 2216mm/s and the measurement precision in the whole measurement range is less than 1%.3. The theoretical model of all-fiber DFB fiber laser self-mixing interference phase modulation system is established and the simulation is carried. In the experiment, we successfully set up the all-fiber DFB fiber laser phase modulation self-mixing interference system.