Three states of operation in the net-normal figure-nine fiber laser at 1560 nm

Abstract

We report an experimental investigation of figure-nine-based Er-doped all-polarization-maintaining fiber laser operating in dissipative soliton regime within the net cavity dispersion ranging from +0.023 ps2 to +0.254 ps2. By changing the width of the spectral filter used inside the resonator, we observed three different states of operation that were dependent on the pumping power and the net cavity dispersion values. Indicated differences in the pulses generated from the two ports can be explained by the interferential work nature of the saturable absorber and the direction-dependent dispersion maps causing two distinct evolutions of pulse profiles. Our findings establish that, depending on the state of the operation, pulses at the reject port can offer at least comparable performance to those at the output port in net-normal mode-locked laser operating at 1.55 μm spectral range. A stability analysis has confirmed the steadiness of generated pulses over time. We examined the tunability of the laser in terms of spectral filter central wavelength and dispersion and their impact on laser operation. To our knowledge, observation of such behavior was not yet reported, and our work contributes to understanding the mechanisms of dissipative soliton generation in the 1.55 μm spectral region.