We used semiconductor optical amplifier as the pumping source and gain medium in laser cavity. We structured two cavities: ring cavity and figure-eight cavity. In the ring cavity, we found two output lights with different wavelengths at 1058nm and 1067nm. Both lights in cavity alternate with high frequency, thus the output detected by a single photodide behaves like a square waveform. In the figure-eight cavity, we generated the highest repetition rate passive mode-locked laser with maximal repetition rate up to 9.1 GHz.