Passive harmonically mode-lock Er3+/Yb3+ codoped double-clad fiber ring laser

The passive harmonically mode-locked fiber ring laser with a small segment of Er3+/Yb3+ codoped double-clad fiber as gain medium, which is pumped by 976 nm LD laser and mode-locked exploiting the nonlinear polarization rotation technique, was successfully demonstrated for the generation of self-starting mode-locked pulses. When the laser was pumped at 2.4 W, stable mode-locked pulses were obtained at the repetition rate of 8.829 MHz through modulating the fiber polarization controllers. The average output power of the fiber laser was 52.5 mW, and the threshold power of the self-starting mode-locked pumping is 0.6 W. The high-order mode-locked, Q-switched and Q-switched-mode-locked pulses were also observed experimentally.