Key Technologies on Large Capacity Optical transmission Networks

The capacity of the optical fiber communication system has increased by more than one thousand times per year in the past forty years. With the emergence of new Internet applications, it cannot meet the demand for huge capacity growth. In this paper, the key technologies for large capacity optical transmission networks are discussed. First, four direct detection optical orthogonal frequency division multiplexing (DDO-OFDM) schemes are studied for short/medium transmission scenarios. Then, coherent optical wavelength division multiplexing (WDM) based on multi-carrier generation technology for long-distance transmission is introduced. Moreover, all-optical wavelength conversion (AOWC) technology is also introduced for coherent optical WDM networks to increase network flexibility.