Enhanced stability of a dispersion-managed, harmonically mode-locked fiber laser

Summary form only given. The high repetition rate and low noise characteristics of the soliton sigma laser have made it a practical source for high-speed telecommunications applications. Considering the high level of harmonic mode locking (N/spl ap/10/sup 4/) at its 10-GHz repetition rate, its low observed pulse dropout ratio of <10/sup -14/ has not previously been explained. A theoretical model indicates that pulse dropouts may be avoided by the use of strong dispersion management in the cavity. A Mach-Zehnder modulator is placed in a loop of polarization-maintaining (PM) fiber. The polarization state of light injected into the non-PM branch evolves in a random manner but is transformed into an orthogonal state by the Faraday mirror; linearly polarized light injected into the branch by the polarizing beamsplitter returns to the beamsplitter also linearly polarized but rotated by 90/spl deg/.