High signal-to-noise ratio fiber laser at 1596 nm based on a Bi/Er/La co-doped silica fiber

We fabricate a high-performance Bi/Er/La co-doped silica fiber with a fluorescence intensity of-33.8 d Bm and a gain coefficient of 1.9 d B/m. With the utilization of the fiber as a gain medium, a linear-cavity fiber laser has been constructed,which exhibits a signal-to-noise ratio of 74.9 d B at 1596 nm. It has been demonstrated that the fiber laser has a maximum output power of 107.4 m W, a slope efficiency of up to 17.0%, and a linewidth of less than 0.02 nm. Moreover, an all-fiber singlestage optical amplifier is built up for laser amplification, by which the amplified laser power is up to 410.0 m W with pump efficiency of 33.8%. The results indicate that the laser is capable of high signal-to-noise ratio and narrow linewidth,with potential applications for optical fiber sensing, biomedicine, precision measurement, and the pump source of the mid-infrared fiber lasers.