Periodic amplification of dark solitons using stimulated Raman scattering

Flexible operability and amplification of gray pulses

We have investigated experimentally the flexible production and amplification of gray pulses for the first time to our knowledge. Switchable wavelengths, tunable pulse-widths, and adjustable contrasts have all been obtained in a fiber laser. Amplification of gray pulses was also experimentally investigated in detail. The contrast of the pulses could also be increased in an amplifier. The robust stability that results from the interactions between adjacent harmonic mode locking counterparts of gray pulses was found to last for up to ten hours. To the best of our knowledge, the gray pulses trains we have generated are the most stable achieved to date in an all-fiber laser system. This finding can be used as a guide for the establishment of robust gray pulses as laser sources.

Gordon-Haus effect on dark solitons

The theory of the Gordon-Haus effect with application to dark solitons is presented. It is proved analytically that a random frequency shift of a fundamental dark soliton results in a time jitter radical2 times lower than that for bright solitons.

Dark-soliton jitter in amplified optical transmission systems

The transmission of dark solitons in ultralong transmission systems with optical amplification is numerically investigated. We show that amplifier noise is responsible for a random frequency shift with a resulting time jitter radical2 times lower than that observed for bright solitons.

Generation of dark solitons under a cw background using waveguide electro-optic modulators

We propose a novel method for generating dark solitons with a cw background by using broadband guided-wave electro-optic modulators. The generated pulse can be amplified by stimulated Raman scattering to permit the observation of soliton effects in the fiber.

Interactions between dark solitons

The interaction forces between two dark solitons are numerically investigated. It is found that dark solitons are less affected than bright solitons by their respective interaction forces. An empirical expression for the separation of two solitons as a function of initial separation and traveling distance is deduced, which agrees well with numerical results.