Passive synchronization of mode-locked Yb-doped fiber lasers

The synchronization of ultrashort pulses is an important research content in laser technology and has important applications in the fields of pump probe, optical frequency metrology, optical coherent synthesis, and nonlinear optics, etc. In this paper, the mode locking of two Yb-doped fiber lasers is realized by nonlinear polarization rotation, and then two circulators are used to make both two laser beams propagate in a piece of fiber. By matching the cavity length of one laser to the other, and with the cross phase modulation of two laser beams in the shared single-mode fiber, two lasers are passively synchronized. Two lasers deliver picosecond pulses near 1.04 μm and 1.05 μm, respectively, and the repetition rate is locked around 38.1100 MHz.