AbstractDigital optical systems represent the current advance in submarine communications. Modern system designs require rapid evaluation of new components without relaxation of the stringent reliability requirements demanded for submarine applications. This article describes the development of integrated circuits (ICs) for submarine use. It goes on to show the design methodology, and discusses some limitations and the demanding reliability assurance aspects. The current IC designs are being used in both long‐haul and short‐haul links. The technology discussed is providing a major role in the future development of high‐capacity optical submarine sy