Soliton propagation with cross-phase modulation and its Modulation Instability in a Nonlinear Chiral Fiber

Abstract

In this paper, we present the stable evolution and instability of left- and right-handed circularly polarized (LCP and RCP) components through single core nonlinear chiral fiber. Considering Maxwell’s equations, and Post’s constitutive relations we derive generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) which govern the evolution of LCP and RCP components. Simulations are based on split-step Fourier method and numerical results reveal the role of GVD and nonlinearity with cooperation to chirality playing in the formation of solitons for LCP and RCP components. The stable evolution of solitons with weak chirality and coupling is discussed. Finally, we have investigated modulation instability (MI) in nonlinear chiral fiber starting from CCNLSEs. Based on theoretical models and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber is analyzed. We have included loss and chirality into account in our analysis and found that loss distorts the sidebands of the MI gain spectrum while chirality modulates the gain for LCP and RCP components, in fact, differently.