CROSS-PHASE MODULATIONAL INSTABILITY IN HIGH-BIREFRINGENCE FIBERS

For the propagation of light in the normal dispersion regime in high birefringence fibers, the existence of cross-phase modulation instability depends critically on group-velocity mismatch between the eigenstates of polarization. In fact, the effect only occurs for non-zero group velocity mismatch. Under these circumstances, the spectral peaks predicted by the nonlinear wave equation occur at frequencies given by the usual phase-marching arguments. For this reason, the cross-phase modulation instability can be identified with four-wave mixing spectra previously observed in birefringen fibers. New experimental data reported in which the predicted cross-phase modulation instability and four-wave mixing spectra are observed by detecting the light exiting a highly birefringent pure fused silica core optical fiber pumped by intense laser pulses at 514.4 nm. © 1990.