Similariton-like Pulse Evolution in an Er-Doped Fiber Laser with Hybrid Mode Locking

An Er-doped all-fiber ultrashort pulse laser with positive total net-cavity group-velocity dispersion is demonstrated based on a hybrid mode-locking mechanism ensured by single-walled carbon-boron-nitrogen nanotubes with coaction of the nonlinear polarization evolution effect. The generation regime with a similariton-like spectrum is obtained. The spectrum width is similar to 31.5 nm, and the minimal pulse duration is similar to 294 fs at full width at half maximum. The average output power is similar to 3.2 mW, corresponding to 0.376 nJ pulse energy and 1.25 kW peak power. The fundamental pulse repetition rate is similar to 8.5 MHz, with a signal-to-noise ratio of 60 dB. The standard deviation of average output optical power stability, measured for 12 h, is about similar to 1% RMS, and the maximum level of relative intensity noise (RIN) does not exceed <-120 dBc/Hz in the 30 Hz-1 MHz frequency range. To prove the similariton-like regime generation, we also studied numerically and experimentally the pulse evolution during propagation through a laser resonator and output single-mode fiber with anomalous dispersion.