Spatial division multiplexing

\u3cp\u3eSpatial division multiplexing (SDM) by employing few-mode fiber or multi-core fiber is expected to efficiently enhance the capacity of optical networks and overcome the anticipated ‘capacity crunch’ due to fast increasing capacity demand. This chapter first introduces the advantages and state-of-the-art of SDM. Second, different SDM technologies and key building blocks such as spatial multiplexer, optical amplifier, wavelength selective switch, splicer, connector and digital signal processing block are thoroughly analyzed. Third, commercialized SDMrelated components are summarized and discussed.\u3c/p\u3