Influence of filter shape and bandwidth on noise-like pulse generation in all-normal-dispersion fiber lasers

We investigate theoretically the laser cavity design in a saturable absorber (SA) mode locked all-normal-dispersion fiber ring laser from which noise-like pulse (NLP) can be generated, highlighting the influence of the inserted filter shape and bandwidth. Theoretically we find that by using a high order super Gaussian profile filter and carefully choosing the filter bandwidth, pulse collapse and sub-pulses collision will happen. With certain choice of the filters in the cavity, we can achieve “L-shape” distribution of noise bursts with extreme peak power pulse, which indicates NLP emission fulfilling ORW criteria.