Effect of the anisotropy on the properties of optical pulses in birefringent optical fibers: Coexistence of the Ordinary and Extraordinary pulse modes

The propagation of polarized compact bright (CB) optical pulses in birefringents optical fibers is examined by focusing on the nonlinear response function of the fiber. The coupled nonlocal nonlinear Schrödinger (CNNLS) equations that include both the Kerr and the nonlocal nonlinearities, governing the simultaneous propagation of the ordinary ( o ) and extraordinary ( e ) pulse modes in nonlinear nonlocal birefringent optical fibers is introduced. This equation takes into account the interaction between the o and the e pulse modes, which has received little attention in the literature. Analytical investigations showed that in the zero-dispersion regime, the fiber admits fast and slow modes CB pulses. These CB pulses are ultra-short pulses (that is pulses with width T 0 ≪ 5 p s ) pulses exhibiting finite supports outside of which they vanish identically and whose formation requires a delicate balance between the nonlinearity and nonlocality of the fiber. We finally showed that the state of polarization of an input polarized optical pulse varies in the fiber during propagation due to the phase birefringence . The results were checked through numerical simulations. • Birefringent optical fibers with nearly instantaneous response are studied. • Two modes co-exist and propagate in birefringents optical fibers in nonlinear regime. • Coupled nonlocal nonlinear Schrödinger equation describing the two modes is derived. • The derived equation admits an ordinary and extraordinary Compact bright pulse mode. • The delay between these modes during propagation is observed.