Noise characterization of the ~915 nm figure-9 mode-locked fiber lasers operating in dissipative and dispersion-managed soliton regimes

In~915 nm neodymium doped fiber lasers, there is a lack of systematic comparative studies on the noise characteristics of different mode locking mechanisms (dissipative solitons and dispersion managed solitons), while the noise performance (intensity/phase noise) directly affects its applicability in core applications such as precision machining, biological imaging, and optical frequency combs. Therefore, based on the nonlinear amplifying ring mirror (NALM) structure, this study constructed two sets of polarization maintaining all fiber lasers with identical cavity structures and core components. By replacing the linear arm reflection element, the controllable switching and comparative study of DS and DMS mode locking mechanisms were achieved. The results indicate that the DMS mechanism benefits from near zero total cavity dispersion and performs outstandingly in suppressing intensity/phase noise; The DS mechanism can effectively suppress intensity noise by utilizing the narrow filtering bandwidth inside the cavity. This study provides experimental evidence for the selection of laser mechanisms for different application scenarios by clarifying the noise characteristics and key parameter differences between the two mechanisms.