The Research Of Characteristics And Related Distance Measurement Based On External Cavity Fiber Laser

Since the birth of the laser in the 1960s, which has experienced 50 years of development. With the rapid development of modern photonics technology, optical fiber communication technology and sensor technology, different types of lasers have been widely used in various fields of industry and agriculture, aerospace, defense, military, health care and scientific research, which are closely related to people’s life. In this paper, we studied the influences of an external cavity feedback on the threshold power, laser linewidth and stability of fiber laser through combining external cavity feedback and fiber laser, as the same time, we also carried out the related research of distance measurement based on the self-mixing effects.The main work of this paper are as follows:1. Based on laser rate equations and steady-state equation,the working principle of external cavity fiber laser was derived, and the simulation of the external cavity feedback effect on the laser output characteristics was carried out.We set up a test system based on external cavity fiber laser and completed the relevant research.2. We built an external cavity feedback tunable fiber laser system by introducing external cavity feedback into tunable fiber laser, and studied the influences of an external cavity feedback on the threshold power, laser linewidth and stability of tunable fiber laser.3. The ranging sensor modelsof semiconductor laser and fiber laser were established based on the combination of self-mixing technology and wavelength tuning technology, and the self-mixing ranging systemsof semiconductor laser and fiber laserwere set up, and the related research was carried out respectively. Experimental results show that the semiconductor laser can be realized ranging range 4cm-60cm and the measurement accuracy within 5mm. Furthermore, the measurement error was analyzed in the paper.The main innovations of this paper include as follows:1. A physical model of external cavity feedback fiber laser system was established and the simulations of the external cavityfeedback effects on the output characteristics of fiber laser and tunable fiber laser, such as threshold power, the laser linewidth and stability, were carried out, which laid a theoretical foundation forsubsequent experimentsand applications.2. The fiber laser and tunable fiber laser systems with external cavity feedback were built, and the influences of external cavity feedback on the output characteristics of laserwere studied. Experimental results show the threshold power reducing from 29.24mW to 24.02mW, linewidth narrowing from 21.4kHz to 17.2kHz. In addition, the tuning range of tunable fiber laser was about 15nm, side mode suppression ratio greater than 66dB and linewidth narrowing from 20.4kHz to 7.3kHz.3. The ranging sensor model of fiber laser was established and the related research were carried out respectively based on the ranging sensor models of semiconductor laser and fiber laser. It laid the foundation for further research of fiber laser in sensing field.