The purpose of OPTICS 2018, the International Conference on Optical Communication Systems, is to bring together researchers, engineers and practitioners interested on any of the optical communication components of an optical communication system, or the system itself. An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. Optical fiber is currently the main means for high-rate transmission in communication networks. In the last years, there is a great deal of ongoing research efforts that span the entire protocol stack of optical networks, with representative areas being architecture of optical components, optoelectronics, wavelength routing, energy efficiency, Quality of Service, hybrid optical-wireless networks etc.