提出和证实了一种光纤环形激光器.将一个带通滤波器与一个带阻滤波器级联,用一段保偏掺铒光纤作为饱和吸收体,得到了一种单纵模双波长光纤激光器.结果表明,该激光器波长间隔为0.4nm,边模抑制比大于49dB.如果将两个波长进行差拍,该激光器有潜力得到49.85GHz的微波信号. A fiber ring laser was proposed and confirmed.A single longitudinal mode dual-wavelength fiber laser was obtained by cascading a band-pass filter with a band-stop filter and using a polarization maintaining erbium-doped fiber as a saturable absorber. It shows that the laser wavelength interval is 0.4nm and the side mode rejection ratio is greater than 49dB. If the two wavelengths are beat, the laser has the potential to get 49.85GHz microwave signal.