Abstract

Modulational instability refers to a parametric four-wave-mixing process in which dispersive waves are phase matched through the compensation of dispersion by the nonlinearity. Owing to the self-focusing Kerr nonlinearity of silica, this purely nonlinear phase-matching process is only possible in the anomalous dispersion regime. However, since the pioneering work of Berkhoer and Zakharov,¹ it is well-known that, when taking into account the additional degree of freedom offered by the polarization of light, purely nonlinear phase matching can be achieved in normally dispersive self-focusing Kerr media. As a result, modulational instability can occur in fibers in the normal dispersion regime. Due to the role of polarization, this instability has been called polarization modulational instability (PM1).

© 1999 Optical Society of America