Polarization instabilities in birefringent fibers: a comparison between continuous waves and solitons

A comparison between continuous waves (cws) and soliton pulses on the bifurcation character for stationary solutions and polarization instabilities in birefringent fibers is presented. For stationary solutions, solitons are shown to demonstrate qualitatively similar bifurcation character to that of cws. The polarization instabilities for solitons are, however, found to differ from those for cws: the fast soliton is unstable even below the bifurcation point and elliptically polarized solitons are all unstable, in contrast to cws, for which the fast mode is unstable only above the bifurcation point and the elliptically polarized modes are all stable. The reason for the difference is discussed.