Passive mode-locked and tunable soliton fiber laser

There has been great interest in the generation of ultrashort pulses from a fiber laser with a nonlinear amplifying loop mirror (NALM). In the past five years, erbium-doped fiber lasers have been developed especially for the use as a simple source of solitons. Various phenomena related to the soliton in the fiber lasers have also been intensively investigated by several research groups. In figure eight lasers, the generated solitons are randomly separated in time within one round trip period and the pulse trains repeat themselves at the same period. The exact pulse pattern and the total number of pulses in one period are highly sensitive to the input pump power. The general principle of operation of the figure eight lasers is understood and many features of its behavior have been explained by several researchers. In this letter, we present the passive mode-locked fiber laser with discrete tunability over the wavelength range from 1540 nm to 1570 nm