Unamplified 220-Gb/s × 20km C-band Transmission using Simplified Heterodyne Detection System

We propose a simple heterodyne detection system for the use in the intra-datacenter networks, and demonstrate the unamplified transmission of a $220-\mathrm{Gb} / \mathrm{s} / \lambda$ signal operating in the C-band over 20 km of the standard single mode fiber by using this system.