A Comprehensive Review of Space Division Multiplexing Techniques and Components In Optical Communication Systems

For several decades, optical communications technology has advanced significantly and steadily, becoming an indispensable resource in our society and economy that are becoming more and more dependent on information. The physical capabilities of single-mode fiber optic cables are approaching their capacity limits. Therefore, to deal with increasing and surprisingly huge bandwidth requirements, other solutions are urgently needed. Space division multiplexing (SDM) was therefore touted as a promising, innovative solution that would significantly increase the optic fiber limit. This paper provides a comprehensive overview of the evolved space division multiplexing (SDM) research, discussing the various categorizations and characteristics of new space division multiplexing (SDM) fibers like fiber bundles, multi-element fibers (MEF), multi-core fiber (MCF), few-mode fiber (FMF), coupled-core fiber (CC), and few-mode multi-core fiber (FM-MCF). Subsequently, we delve into the research accomplishments associated with each of these fiber types. Furthermore, this paper examines the advancements in amplifier technology as well as multiplexer/demultiplexer technology. Lastly, we do inter-fiber type comparisons.