980-nm all-fiber mode-locked Yb-doped phosphate fiber oscillator based on semiconductor saturable absorber mirror and its amplifier |
(a) Stable mode-locked pulse train of 980-nm Yb-doped fiber laser at a repetition of 17.08 MHz, and (b) the stable mode-locked pulse train of 980-nm Yb-doped fiber laser at a repetition of 20.96 MHz. |