超低阈值Q调制，锁模Yb3+光纤环型腔激光器的实验研究

he experimental study of a passive mode-locked Yb3+-doped fiber laser is reported, the cavity utilize “8” font ring instrument in which SESAM is subtly introduced, as well as the polarizer and polarization controllers. Combining the effect of non-linear polarization rotation with the self-starting of SESAM, we achieved stable operations of Q-switched and CW mode-locked regime at the low pump power. When the pump power is 18 mW, we obtain the Q-switched pulse which repetition is16 kHz, pulse width is 4 μs ,and output spectrum width is 2.34 nm. When the pump power is 60 mW, we obtain the mode-locked pulse which output power is 8 mW, repetition is 20 MHz, output spectrum width is 3.54 nm, pulse width is ps or sub ps orders, we also observe the tunable phenomenon with proper adjustment of the polarization controllers’ orientations, tunable range is 1028~1053 nm.