Cladding-pumped passive harmonically mode-locked fiber laser

All-fiber fundamentally mode-locked 12 GHz laser oscillator based on an Er/Yb-doped phosphate glass fiber

We have developed a compact and stable all-fiber fundamentally mode-locked 12 GHz laser system. The passively mode-locked laser centered at 1535 nm has temporal pulse width of ∼2  ps and average power of 5 mW. The timing jitter, which is cumulative from pulse-to-pulse, has been measured using an optical cross-correlation method and found to be 44  fs/pulse. The self-starting, mode-locked laser consists of a semiconductor-based saturable absorber with high modulation depth and a high gain per unit length, polarization-maintaining 0.8 cm long Er/Yb phosphate fiber as a gain medium.

Transition dynamics for multi-pulsing in mode-locked lasers

We consider experimentally and theoretically a refined parameter space in a laser system near the transition to multi-pulse modelocking. Near the transition, the onset of instability is initiated by a Hopf (periodic) bifurcation. As the cavity energy is increased, the band of unstable, oscillatory modes generates a chaotic behavior between single- and multi-pulse operation. Both theory and experiment are in good qualitative agreement and they suggest that the phenomenon is of a universal nature in mode-locked lasers at the onset of multi-pulsing from N to N +1 pulses per round trip. This is the first theoretical and experimental characterization of the transition behavior, made possible by a highly refined tuning of the gain pump level.

Passive harmonic mode locking with a high-power ytterbium-doped double-clad fiber laser

We report passive harmonic mode locking of a high-power Yb-doped double-clad fiber laser operating in both the normal- and the anomalous-dispersion regimes with a fundamental repetition rate of 20.4 MHz. In the normal-dispersion regime, 116-fs, 1.7-nJ pulses are emitted at a repetition rate of 102 MHz. The results indicate a supermode suppression of more than 60 dB. In the anomalous-dispersion regime, 1-ps, 125-pJ pulses are emitted at a higher repetition rate of 408 MHz.

Stable single- and dual-wavelength fiber laser mode locked and spectrum shaped by a Fabry-Perot saturable absorber

We show that the spectral response of a Fabry-Perot semiconductor saturable absorber depends on laser beam focusing. We used this effect to achieve stable passive mode-locked operation in a simple and environmentally stable fiber laser by introducing spectral filtering and forcing near-resonant operation. By reducing the free spectral range and increasing the nonlinear response of the Fabry-Perot saturable absorber, we obtained dual-wavelength mode-locked operation.