Beyond 1-Tb/s Superchannel Transmission

Recent progress on high-speed optical transmission with per-channel data rates beyond 1 Tb/s using multi-carrier superchannel architectures is reviewed. Various superchannel implementations based on orthogonal frequency-division multiplexing and quasi-Nyquist wavelength-division multiplexing are discussed and compared. 1. Introduction To satisfy the ever-increasing capacity demand in optical fiber communications, the data rate carried by each wavelength channel in optical transport systems has been increasing at a very fast pace [1-3]. 100-Gb/s per-channel data rates have are now available in commercial systems, and data rates of 1-Tb/s and beyond are under active research [4-10]. Multi-Terabit superchannels have also led to a re-thinking of spectral bandwidth allocation beyond the current fixed grid architectures, allowing for more efficient spectral utilization. One promising method to realize per-channel data rates beyond 1 Tb/s is based on the multi-carrier superchannel architecture, in which multiple optical carriers are modulated and multiplexed together at high spectral efficiency (SE), e.g., via orthogonal frequency-division multiplexing (OFDM), and are received together at an intended destination after fiber transmission. The term "superchannel" was first coined by S. Chandrasekhar et al. [6] for multiple single-carriermodulated signals arranged under the optical OFDM condition, although the use of optical OFDM to group multiple modulated bands together was previously demonstrated in the context of OFDM-modulated signals [4,11] and in the context of 2-carrier transmission [12].