We proposed an all-fiber tunable distributed Bragg reflector (DBR) laser rangefinder, which realized high-accuracy measurement of the absolute distance in the range of 1.88 to 3.33 m based on the self-mixing effect. The theoretical analysis of the all-fiber tunable DBR laser shows that wavelength tuning range and frequency of the laser can influence the measurement range and resolution. In addition, the experimental results indicate that the influence factors of measurement accuracy and sensitivity in absolute distance measurement are modulation response linearity, experimental equipment, and circuit bandwidth, which is in good agreement with theory analysis. Moreover, increasing the linear wavelength tuning range of the tunable DBR laser is an essential method to improve the measurement accuracy and sensitivity of the absolute distance measurement system.
A compact external cavity fiber laser has been proposed by using a silver diaphragm as the end-coupled cavity of Distributed Bragg Reflector. In this paper, structure and performance of the optimized all-fiber laser with external cavity is in good agreement with the theoretical analysis and numerical simulation. Meanwhile, experimental results demonstrate that the external cavity laser based on Distributed Bragg Reflector fiber laser could reduce threshold pump power from 25.6mW to 24.0mW and narrow the linewidth from 28.3kHz to 16.4kHz.