Linear Propagation Models for Optical Systems with Space-Division Multiplexing with Coupled Channels

• Grant number: 22/05753-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: September 05, 2024
• Field of knowledge: Engineering - Electrical Engineering - Telecommunications
• Principal Investigator: Darli Augusto de Arruda Mello
• Grantee: Humberto Vinícius Queiroz Melo
• Host Institution: Faculdade de Engenharia Elétrica e de Computação (FEEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 15/24341-7 - New strategies to confront with the threat of capacity exhaustion, AP.TEM
• Associated scholarship(s): 23/10456-3 - Selective excitation for SDM transmission with a limited number of transceivers, BE.EP.IC

Abstract

Current high-capacity coherent optical systems implement wavelength multiplexing and polarization multiplexing, supporting the massive transmission of Internet traffic. However, new multiplexing and device integration techniques are required to sustain the exponential growth of traffic and avoid the consequent increase in costs per bit. In this scenario, space-division multiplexing (SDM) multiplies the capacity of optical systems by exploiting parallel spatial paths. SDM systems can be implemented using bundles of single-mode optical fibers, multicore fibers, multimode fibers, or hybrid few-mode multicore fibers.The transmission of signals in coupled-core multicore fibers or few-mode fibers is prone to channel coupling. In coupled transmission, digital signal processing techniques are required at the receiver, with multiple-input multiple-output equalization (MIMO) to recover the transmitted information. In addition to mode coupling, coupled SDM transmission also introduces modal dispersion and mode-dependent loss or gain (MDL or MDG), perturbations that increase the complexity of the MIMO equalizer and limit the system capacity. This undergraduate research project aims to revisit the fundamental concepts of SDM transmission technologies with coupled channels, with particular attention to analytical and computational SDM channel modeling. We will implement a multisection model for coupled SDM transmission considering the effects of modal dispersion, MDG and MDL. The channel capacity will be studied from an information-theoretical perspective considering a MIMO additive white Gaussian noise channel. The average, outage and minimum capacities will be evaluated. Adaptive equalization algorithms will be implemented for evaluating the capacity distribution a PDL-impaired system, as a particular case of the MDG with only two polarization modes. Finally, we consider carrying out experimental PDL measurement at the University College London (UCL) laboratories in the United Kingdom.