Dissipative soliton resonance in a passively mode-locked figure-eight fiber laser

The generation of mode-locked rectangular pulses operating in dissipative soliton resonance (DSR) region is demonstrated in an erbium-doped figure-eight fiber laser with net anomalous dispersion. The duration of the wave-breaking-free rectangular pulse broadens with the increase of pump power. At a maximum pump power of 341 mW, the pulse energy can be up to 3.25 nJ with a repetition rate of 3.54 MHz. Particularly, the spectrum of rectangular pulse operating in DSR exhibits conventional soliton sidebands. The observed results show that the formation of pulse operating in DSR region is independent of mode-locking techniques, which may be helpful for further understanding the DSR phenomenon.