Vector harmonic mode-locking by acoustic resonance

For an Er-doped fiber laser, for the first time, to best of our knowledge, we demonstrate both experimentally and theoretically a novel mechanism harmonic mode-locking based on electrostriction effect leading excitation torsional acoustic modes in transverse section laser. The exited modulate birefringence that results synchronization oscillations at linewidth narrowing with increased signal-to-noise ratio 30 dB. By adjusting in-cavity tuning polarization controller, enable selection mode be stabilized.