Issue link: https://www.e-digitaleditions.com/i/1066130
January/February 2019 I 51 400 Gb LAYER-1 CONNECTIVITY: Total Cost of Ownership for Singlemode Optical Fiber Based Infrastructure INTRODUCTION Over the last decade, optical Ethernet based LAN connectivity has evolved rapidly, generating several options with each serving a specific set of applications. Today, the industry is deploying 100G (Gb) connectivity, especially in medium to large data centers; some of the hyperscale data centers are already planning for 400 Gb in the next few years. There are several options for providing 400 Gb data center connectivity 1 . Broadly, the optical transceiver architectures for singlemode optical fiber connectivity can be categorized into two: one based on parallel optics where multiple lower speed signals are transmitted via independent fibers; the other architecture is based on wavelength division multiplexing where multiple optical fiber channels with wavelength diversity are multiplexed and transmitted over single fiber. The most popular devices for 100 Gb connectivity are PSM4 (parallel single mode – four lane) 2 and CWDM4 (coarse wavelength division multiplexing – four lane). 3 By Mike Connaughton, RCDD and Rakesh Sambaraju