Role of dispersion in limiting pulse width in fiber lasers

Generation of spectral sidebands is characteristic of ultrashort soliton all-fiber lasers. We relate the generation of these sidebands to a loss mechanism dependent on the pulse duration and total cavity dispersion. We confirm experimentally using an erbium figure eight laser that the minimum pulse duration is therefore limited by the total dispersion. Short cavities constructed from low-dispersion components allow shorter pulses to be obtained, and we demonstrate pulse durations as short as 160 fs.