Study On Stability Of 1.55μm-Single-Frequency Fiber Laser

Due to the advantage of mode-hop, extremely narrow linewidth, low noise and all-fiber structure and so on, DBR single-frequency fiber laser has been a hot research topic near the 20 years. Single frequency fiber lasers have a broader application prospects in high-precision optical fiber sensing, LIDAR, coherent optical communication and seismic wave detection and other fields. Recently, the applications of fiber laser have been more widely and more increasingly, high precision, anti-jamming and stability have become key issues that must be addressed. Because the DBR single-frequency fiber laser is susceptible to the external environment, especially temperature(high temperature and low temperature), currently fiber lasers used in laboratory work at the temperature between 15 ℃ and 35 ℃ over which range the indicator of parameters that a single-frequency fiber laser operates is unstable. In order to solve the above problems, this thesis studies the production process of the cavity and enables it to withstand lower temperatures and higher temperatures.Based on introducing the working principle, the basic structure and implementing method of single-frequency fiber, this thesis describes the stability technologies of a fiber laser: power stability, frequency one and other key stable technologies. It studies the stability of 1.55 μm polarized cavity through single-longitudinal-mode range, output power, wavelength, power stability, and extinction ratio. It also studies the stability of 1.55μm polarized cavity through production process which makes the cavity working more stable so that the produced cavity should meet the following requirements: the size of single longitudinal mode should be stable, single longitudinal mode critical point drift should not exceed 0.5 ℃, extinction ratio greater than 20, instability of the power is less than 2%, the wavelength must be near at 3pm range at the same temperature, the output power of slow axis should be greater than 5mW with 980 nm pump source with pumping current 150 mA, and it should withstand a wider temperature range(the highest temperature 50 ℃ and the lowest temperature 10 ℃).This thesis proposes a wavelength measuring method for measuring single longitudinal mode interval of 1.55μm polarization-maintaining fiber laser, and compares it with other measuring methods such as spectral scanning, F-P cavity. The experiment results show that the three measuring methods can achieve the same result and that the wavelength measuring method can be used for measuring the single longitudinal mode interval of 1.55 μm polarization-maintaining fiber laser.