Optical Amplifiers for Access and Passive Optical Networks: A Tutorial

For many years, passive optical networks (PONs) have received a considerable amount of attention regarding their potential for providing broadband connectivity, especially in remote areas, to enable better life conditions for all citizens. However, it is essential to augment PONs with new features to provide high-quality connectivity without any transmission errors. For these reasons, PONs should exploit technologies for multigigabit transmission speeds and distances of tens of kilometers, which are costly features previously reserved for long-haul backbone networks only. An outline of possible optical amplification methods (2R) and electro/optical methods (3R) is provided with respect to specific conditions of deployment of PONs. We suggest that PONs can withstand such new requirements and utilize new backbone optical technologies without major flaws, such as the associated high cost of optical amplifiers. This article provides a detailed principle explanation of 3R methods (reamplification, reshaping, and retiming) to reach the extension of passive optical networks. The second part of the article focuses on optical amplifiers, their advantages and disadvantages, deployment, and principles. We suggest that PONs can satisfy such new requirements and utilize new backbone optical technologies without major flaws, such as the associated high cost.