Analog Radio-Over-Multi-Mode Fiber: A Spectral Efficiency Perspective

Multi-mode fiber (MMF) significantly increases data rates by spatially multiplexing over parallel optical channels. Analog radio-over-fiber (A-RoF) achieves lower latency and greater bandwidth as compared to digital systems but is limited by nonlinear interference in single-mode fiber (SMF). MMF reduces this interference by transmitting signals across multiple spatial modes. In this work we present a MMF aided A-RoF model for uplink MIMO systems. The linear model considers fiber impairments and noise propagation over the optical and wireless link, assuming an optimum receiver at the baseband unit. We compare the spectral efficiency of MMFaided A-RoF with wavelength division multiplexing (WDM) aided A-RoF, showing MMF reduces nonlinear interference and supports higher data rates, though it is limited by a number of optical modes and wireless channels.