Equalization for Optical PAM Data Center Interconnects

With the rapid development of optical data center interconnect, the requirement for data rate of client-side transceivers increases drastically. To meet the transmission rate demand, the recent pulse-amplitude modulation optical interconnects are discussed. To lower down the cost of the optical interconnects, low cost opto-electronic devices with strong bandwidth limitation and nonlinear distortion are employed. Moreover, the interplay between the fiber dispersion and square law photodetection leads to additional nonlinear inter-symbol interference. To handle the problem, various digital equalizers are introduced, which are reviewed in this paper.