we demonstrate a stable high-q microring resonator (mrr)-based pulsed laser source with adjustable repetition rate from 49 to 735 ghz, corresponds to repetition rate multiplication of up to 15x the free spectral range (fsr) of the mrr. the repetition rate multiplication is realized by temporal multiplexing multiple pulses in the mrr through simply tuning of the fiber cavity length. thus, the repetition rate of the pulsed laser source breaks the frequency limitation of the previous dissipative four wave mixing based mode locked lasers whose repetition rate is equal to the fsr of the built in comb filter. this high quality chip-based repetition rate multiplicable pulsed laser source is an effective approach to on-chip ultrahigh speed optical clock frequency multiplication systems.