An erbium-doped fiber laser with all-fiber Mach–Zehnder interferometer (MZI) and tunable filter was proposed and experimentally demonstrated. In the designed fiber laser, 6 m C-band erbium-doped fiber was selected as a gain medium; the MZI comprised two waist-enlarged fiber bitapers. In the experiment, the laser threshold was 93 mW, whereas a switchable single-longitudinal-mode laser was realized within 1519.7–1564.6 nm by adjusting the tunable filter and the line interval was less than 2.5 nm; for single-wavelength laser, the peak power difference of each line was less than 4 dB, and the power fluctuation was less than 0.77 dB within 10-min scan time. A stable and switchable dual-wavelength laser was realized, the wavelength spacing of each dual-wavelength laser was less than 0.7 nm, the side-mode suppression ratio was more than 30.2 dB, and the power shift was less than 0.39 dB. The laser’s 3-dB linewidth was less than 0.1 nm.

提出并通过实验证明了掺fiber光纤激光器，该激光器具有全光纤马赫曾德尔干涉仪（MZI）和可调滤波器。在设计的光纤激光器中，选择了6 m C波段掺光纤作为增益介质。MZI包括两个腰部扩大的光纤尖嘴钳。在实验中，激光阈值为93 mW，而通过调整可调滤光片，可在1519.7–1564.6 nm范围内实现可切换的单纵模激光，并且行距小于2.5 nm。对于单波长激光器，在10分钟的扫描时间内，每条线的峰值功率差小于4 dB，并且功率波动小于0.77 dB。实现了稳定，可切换的双波长激光器，每个双波长激光器的波长间隔小于0.7 nm，侧模抑制比大于30.2 dB，功率偏移小于0.39 dB。激光器的3 dB线宽小于0.1 nm。