Bidirectional all-PM Er-doped fiber laser based on a self-stabilized interferometer mode-locker

We demonstrate a bidirectional all polarization-maintaining (PM) Er-doped fiber laser based on a self-stabilized interferometer mode-locker. By utilizing mechanical sharing and multiplexing propagation directions, the laser has balanced bidirectional outputs and passively suppresses common-mode noise. We also investigate the intracavity pulse dynamics via numerical simulations, which coincides well with experimental observations. The self- stabilized interferometer compensates for the group delay difference between the polarization components induced by linear birefringence. The cross-phase modulation effect in the self-stabilized interferometer leads to asymmetric spectra. In addition, from 10 kHz to 1 MHz frequency range, the integrated RMS phase noise in clockwise (CW) and counter-clockwise (CCW) directions are 0.124 mrad and 0.14 mrad, respectively. The integrated RMS RIN in CW and CCW directions are 439 ppm and 464 ppm. Due to passive common-mode noise cancellation, the repetition frequency difference can be stabilized near 19 Hz in 2500 s gate time. The stability of the repetition frequency difference can reach a minimum value of 4.167 x 10-4-4 at a gate time of 100 s. This novel bidirectional all-PM Er-doped fiber laser based on a self-stabilized interferometer mode-locker can provide a new scheme for the construction of an all-PM dual-comb system.