Numerical simulations of small core microstructure fibers showed that loss of coherence in continuum generation is better maintained as the launched pulse becomes shorter. For instance, for pulses shorter than 100 fs the coherence was maintained along the continuum [1]. Recently, low dispersion slope, dispersion shifted highly nonlinear fibers was used to demonstrate coherent supercontinuum generation at 1550 nm with low power femtosecond pulses [2].
Polarization mode dispersion starts to become a serious problem in fiber optic communication systems operating at 10 Gb/s per channel and up. In an optical fiber link the PMD is characterized by differential group delay which is the time delay between the two principal states of polarization. However, both the differential group delay and the two principal states of polarization vary randomly with wavelength giving origin to higher order PMD. They drift also randomly with time due to environmental variations. It means that any compensation scheme has to adapt dynamically to these random variations.
[1] J. M. Dudley et al, Optics Letters, 27, 1180, 2002.
[2] J. Nicholson et al, OFC’2003, page 511.