Single Wavelength Tunable Ultra Wideband Erbium-Doped Fiber Laser Based On Double-Loop Pumping Regulation

In recent years,fiber laser has become a research hotspot in optical communication.However,for Erbium-doped fiber lasers,there are still problems such as the tuning bandwidth is not wide enough and the output spectral power is not stable enough.From the point of view of tuning bandwidth and flat bottom noise,under double annular cavity pumping,using Fabry-Perot(F-P)tunable filter(FOTF)and Sagnac ring in the single-wavelength Er-doped fiber laser is proposed and experimentally verified.In order to design this system,the following work has been done:1.After being familiar with the research background and history of fiber lasers,I have learned the important components of fiber lasers and the structure and principle of lasers.How to achieve laser output and the required conditions are analyzed.2.In order to select appropriate optical devices,understand the principle behind each device,understand the role of each device,analyze and deduce theoretically,and study the relationship between optical path direction,output spectrum and experimental structure.3.This paper proposes a dual-ring cavity pumped tunable erbium-doped fiber laser.The fiber laser adopts the structure of F-P manual tunable filter,and uses Sagnac ring as the filter system to obtain good tuning accuracy.The pump source and erbium-doped fiber amplifier are used to adjust the output light to obtain a good flat spectrum.And 600 m SMF is added to reduce mode competition,so as to output more stable laser spectrum.The experimental results show that the tuning range of the single-wavelength tunable laser can reach 60 nm,while the tuning range of the flat output spectrum is increased from 20 nm to 30 nm,and the side-mode rejection ratio is up to 52 dB,and the linewidth of 3 dB is about 0.05 nm,which can realize the stable single-mode narrow bandwidth output of the laser.The laser proposed in this paper can obtain stable and wide single-wavelength tunable range,which provides ideas for the research and development of single-wavelength tunable lasers with tuning bandwidth and stable tuning waveform,and has important value.