Solitons

Pulse spreading is a concern in signal communication where light and optical fibers are used.  Pulse spreading reduces the bandwidth and lowers data capacity of fiber communication. Pulse spreading can be minimized by operating at zero-dispersion wavelength. Pulse spreading becomes minimum when we use highly coherent light with very small spectral width. Production of solitons is a new method where a pulse (soliton) which travels along a fiber without changing shape is produced. Formation of soliton is possible only if the initial pulse possess a peak energy and pulse shape.  Here the product of pulse width and pulse energy should be a constant value and must be dependent on the magnitudes of the dispersion and non-linearity.  Due to the non-linear compensation, solitons are formed only at wavelengths longer than the zero dispersion wavelengths in glass fibers.  Pulse spreading is less in solitons but attenuation remains. Therefore periodical amplification is required for solitons.