Rejuvenating direct modulation and direct detection for modern optical communications

Abstract

High-speed transoceanic optical fiber transmission using direct modulation (DM) and direct detection (DD) was one of the most stirring breakthroughs for telecommunication in 1990s, which drove the internet as a global phenomenon. However, the later evolution of optical coherent communications in 2000s gradually took over the long-haul applications, due to its superior optical spectral efficiency. Nowadays, DM–DD systems are dominant mainly in cost- and power-sensitive short-reach applications, because of its natural characteristics—the simplicity. This paper reviews the recent advances of DM–DD transceivers from both hardware and signal processing perspectives. It introduces a variety of mod..