The highly stable 5.3 ps wide optical pulse source with a repetition rate of 10 GHz, and 184 fs timing jitter is reported. 10 GHz optical pulses generated by a deeply directly modulated laser (DML)enter a LiNbO3 electroopitc phase modulator to enhance the negative chirp and enlarge pulse width, and pass through dispersion compensation fibers (DCF) to compress chirps. The optical pulses generated by DML have negative chirp, and phase modulation can generate both positive and negative chirp at different timing intervals. By appropriately tuning optical time delay before optical pulses enter the phase modulator, the output optical pulses can have more negative chirp. Then, the chirped optical pulses can be compressed into low timing-jitter short pulses without pedestal by positive dispersion fiber.