OAM Modes in Optical Fibers for Next Generation Space Division Multiplexing (SDM) Systems

Due to the renewed demand on data bandwidth imposed by the upcoming capacity crunch, optical communication (research and industry) community has oriented their effort to space division multiplexing (SDM) and particularly to mode division multiplexing (MDM). This is based on separate/independent and orthogonal spatial modes of optical fiber as data carriers along optical fiber. Orbital Angular Momentum (OAM) is one of the variants of MDM that showed promising features including the efficient enhancement of capacity transmission from Tbit to Pbit and substantial improvement of spectral efficiency up to hundreds (bs-1 Hz-1). In this chapter, we review the potentials of harnessing SDM as a promising solution for next generation global communications systems. We focus on different SDM approaches and we address specifically the MDM (different modes in optical fiber). Finally, we highlight the recent main works and achievements that have been conducted (in last decade) in OAM-MDM over optical fibers. We focus on main R&D activities incorporating specialty fibers that have been proposed, designed and demonstrating in order to handle appropriates OAM modes

Multiplexing, Transmission and De-Multiplexing of OAM Modes through Specialty Fibers

Space division multiplexing (SDM) over fibers has introduced a new paradigm in optical communication thanks to its capability to meet the ever-renewed demand of more transmission capacity and on large spectral efficiency. This ever-increasing demand is pushed by the nonstop increase of the number of connected users, devices, processes, and data (toward internet of everything IOE). One of the most promising variants of SDM, that has recently shown great potential, is based on harnessing orbital angular momentum (OAM) modes as data carriers. These OAMs are multiplexed, transmitted over special optical fibers (OAM-fibers) then de-multiplexed. In order to highlight the potential of SDM system incorporating OAM modes through fibers, in this chapter, we disassemble an SDM system and we examine its main key elements. The potential of OAM-SDM is discussed as a promising candidate for the next generation local/global communications networks. This chapter is intended to provide a comprehensive and deep understanding of SDM, which will push R&D community to derive future research directions in the field

Design of elliptical photonic crystal fiber (E-PCF) for the transmission of 116 OAM channels across the S, C, L and U bands

Orbital angular momentum (OAM) modes over photonic crystal fibers (PCFs) have shown great capability in unleashing the available data rates in optical communication systems. In this paper, we propose and numerically design a novel elliptical photonic crystal fiber (E-PCF) using assisted Germania-doped silica as a material background and elliptical air holes. Using a systematic scanning methodology, we adjusted the E-PCF key parameters with the aim to explore appropriate designs that support large number of OAM channels featuring low confinement loss (CL). Numerical simulations using finite element method (FEM) show the supports of large number of independent/separate OAM channels (116 OAM with Δneff≥ 10−4). A detailed numerical modal analysis has been carried out over the S + C + L + U communication bands show that the designed E-PCF handles robust OAM modes. This includes low chromatic dispersion (CD = 92 ps/km/nm), low differential group delay (<60 ps/km), high effective mode area (max Aeff = 124 µm2), low nonlinearity coefficient (γ < 2.6 /W/m) and low confinement loss (Max CL = 2.07 × 10−4 dB/m). The obtained results and the comparisons with those recently reported in literature shows that the designed E-PCF could find applications in next-generation optical communication systems that uses OAM modes as data carriers