this paper reports on a diode-pumped picosecond passively mode-locked yb:sso laser. pulses as short as 2.3 ps with a repetition rate of 53 mhz were generated, without extra negative dispersion elements. the output power achieved 1.87 w at a pump power of 11.5 w. continuouswave operation and wavelength tuning were examined. the cw operation achieved 3.55 w output power with a slope efficiency of 44.5%; its tuning can cover the range of 1034.0-1089.7 nm.