We demonstrated a wavelength tunable

hybrid mode-locking fiber ring laser incorporating a dispersion-imbalance sagnac loop

which is formed by a polarization controller

one segment of single mode fiber

one segment of dispersion shifted fiber and an additional coupler with the splitting rate of 50:50. With 10-GHz signal modulation of the modulator

the pulse duration at the repetition rate of 9.997140 GHz was less than 27.5 ps.