Optimized Noise Performance in All-PM Linear Mode-Locked Fiber Oscillators through Mitigation of Cross-Phase Modulation

Here, we demonstrate improved noise performance and pulse quality of fiber oscillators mode-locked with all-PM, linear self-stabilized interferometers (LSI) through intra-cavity suppression of cross-phase modulation (XPM) in both soliton and stretched-pulse regime. A modified LSI oscillator setup is constructed, which allows to switch between standard configuration, and a performance-enhanced configuration with XPM suppression via implementation of a highly birefringent intra-cavity crystal. Comparative measurements in soliton and stretched-pulse regime verify not only a drastically improved time-domain output pulse shape and spectral quality, but further a significant suppression of timing-jitter and relative intensity noise (RIN) for the XPM-suppressed laser configuration. In soliton regime, up to ~3.5 dB reduction in integrated timing-jitter (9 kHz - 5 MHz) are verified from 87 fs to 39 fs RMS, and a suppression of integrated RIN (1 Hz - 5 MHz) from 0.08% to 0.06%. Correspondingly, in stretched-pulse regime, the integrated jitter (3 kHz – 5 MHz) is reduced from ~22 fs down to 14.5 fs RMS and the integrated RIN (1 Hz - 5 MHz) from ~0.07% to 0.04%.