Ultra-short pulse propagation model for multi-core fibers based on local modes

Abstract

Multi-core fibers (MCFs) have sparked a new paradigm in optical communications and open new possibilities and applications in experimental physics and other fields of science, such as biological and medical imaging. In many of these cases, ultra-short pulse propagation is revealed as a key factor that enables us to exploit the full potential of this technology. Unfortunately, the propagation of such pulses in real MCFs has not yet been modelled considering polarization effects or typical random medium perturbations, which usually give rise to both longitudinal and temporal birefringent effects. Using the concept of local modes, we develop here an accurate ultra-short pulse propagation model that rigorously accounts for these phenomena in single-mode MCFs. Based on this theory, we demonstrate analytically and numerically the intermodal dispersion between different LP01 polarized core modes induced by these random perturbations when propagating femtosecond pulses in the linear and nonlinear fiber regimes. The ever-decreasing core-to-core distance significantly enhances the intermodal dispersion induced by these birefringent effects, which can become the major physical impairment in the single-mode regime. To demonstrate the power of our model, we give explicit strategies to reduce the impact of this optical impairment by increasing the MCF perturbations.

Optical core-to-core crosstalk in rod-type multicore fibers

“…Additionally, optical crosstalk should be prevented in MCFs that are used for ultrashort pulsed operation and/or coherent combination, since it would lead to significant pulse distortions together with a reduction of the system performance. [5] In this work we will show that detrimental crosstalk can still occur in laser-active, rod-type MCFs with step-index cores and lengths in the range of just a few meters. Fig.…”

Supersymmetric Transformations in Optical Fibers

“…For this value of peak power, the pulse distortion induced by the nonlinear effects of the optical medium can be neglected [51]. …”

“…The GVD should be considered only in a given LP m;n mode when L > L GVD ¼ T 2 P =β 2;m;n , where β 2;m;n ¼ d 2 β m;n =dω 2 [52]. Typically, β 2;m;n is of the order of −20 ps 2 =km or lower in weakly guiding silica fibers [51][52][53]. Thus, since L ≪ L GVD ∼ 2 × 10 7 km, we can neglect the pulse distortion induced by the GVD in Fig.…”

Ultra-wide bandwidth all-solid specialty bandgap fiber for ultrashort pulse delivery

“…However, the limitations on bandwidth tunability still exist in such hollow-core geometries, and their structural fragility makes them less suitable for typical long distance applications. As an alternative approach, an analytical model of ultrashort pulse propagation in linear as well as nonlinear regime has been demonstrated using the concept of local modes in a multimode fiber (Macho Ortiz et al, 2017). Although, such multicore platforms have potential to greatly enhance the transmission bandwidth, but the complexities in their design, analysis and fabrication pose a challenge.…”