Beat frequencies of up to 16 THz generated via modulation instability in birefringent fibres

Modulation instability can occur in the normal dispersion regime only via cross-phase modulation. In a high birefringence fiber, cross-phase modulation between the pump waves on the two principal axes of the fiber generates two modulation instability sidebands separated by a frequency which is primarily determined by the birefringence and dispersion of the fiber, with a secondary dependence on the pump power. The superposition of these sidebands can generate an amplitude modulated pulse with modulation frequencies of up to 16 THz.