Single-pump parametric amplification in randomly birefringent unidirectionally spun fibers

A systematic study of the effects of polarization-mode dispersion (PMD) on broadband and narrowband single-pump fiber parametric amplifiers is realized through numerical solutions of the equations governing the interaction. The nonlinear polarization rotation is shown to be a relevant effect that can increase gain randomness when it mixes with PMD. In unidirectionally spun fibers, the signal-pump alignment, and hence the gain, can be highly enhanced, and nonlinear polarization rotation effects appear for larger PMD values. In spite of the enhanced alignment, for large PMD, the interaction becomes inefficient and the gain decreases to zero.