Author : Elaine Shin-Yeu Chou
Publisher :
Page : pages
File Size : 18,88 MB
Release : 2021
Category :
ISBN :
The exponential growth trend of network traffic during the past few decades continues to be driven by emerging applications. As global traffic demands rise, the share of traffic carried by optical fiber is increasing simultaneously. Therefore, it is imperative that future optical fiber links take full advantage of the resources available to maximize capacity. This work aims to apply communication theory concepts and signal processing techniques to optical communication links to ultimately increase capacity in systems that are subject to component limitations. First, we explore the advantages of adaptive-rate access networks, implemented through adaptive coding and modulation that adjusts the forward error correction code rate and modulation order in response to the channel conditions of each user. Our adaptive coding and modulation scheme can achieve an equalized bit rate of 40 Gb/s with 25G-class components on a network with fiber lengths of 5 to 25 km. Next, we study the fundamental performance of Kramers-Kronig detection, a technique that uses signal processing to retrieve the phase of a signal from its intensity measurement, making comparisons to standard coherent detection and standard direct detection. Finally, we study the benefit of successive interference cancellation in frequency-selective space-division multiplexed ultra-long-haul submarine links with mode-dependent gain caused by optical amplifier limitations. We show that successive interference cancellation, in conjunction with coding across modes, decreases capacity loss resulting from mode-dependent gain by 39% at 15,000 km and increases system reach by 28% compared to minimum-mean-square error detection in a link with moderate mode-dependent gain.