Cascaded Cross-Phase Modulation Instability in the Normal Dispersion Regime of a Birefringent Tellurite Microstructured Optical Fiber

Cascaded cross-phase modulation instability (XPMI) is experimentally observed in the normal dispersion regime of a birefringent tellurite microstructured optical fiber (BTMOF). At the average pump power of ~33 mW, cascaded XPMI with nine stokes sidebands and six antistokes sidebands is observed in a 3-m BTMOF. To the best of our knowledge, this is the first demonstration of cascaded XPMI in nonsilica optical fibers. The influence of fiber length variation on the evolution of cascaded XPMI is investigated by using a 0.3-m BTMOF. At the same pump power, cascaded XPMI with only eight stokes sidebands and five antistokes sidebands is observed. This is because shorter fiber length leads to lower nonlinear effect, which in turn induces less obvious XPMI effect.