Evolution of optical networks: from legacy networks to next-generation networks

Abstract The requirement for the huge bandwidth-demanding applications has urged researchers to develop improved data pipes that could allow smooth data flow. Revolutionary growth has been witnessed in the domain of the telecommunication industry, which has opened new horizons for connectivity among humans and devices alike especially, in the era of 5G. The advancement from TDM multiplexed signal transmitted over copper wire to the flexible and smart grid along with ethernet passive optical networks or space division multiplexed over optic fiber introducing enormous speed in 100 of Gbps has contributed to the fastest communication. The heterogeneous structure and network complexity require the automating of telecommunication services which have been assisted with the incorporation of machine learning and artificial intelligence, highlighting the new era of communication with the reliability and fastest accessibility. This survey reports the evolution of optical carrier generations and advancement in networks along with the fundamental achievements to comprehend the supportive competition while highlighting the gaps and challenges for future work.