By Haipeng Zhang, Ph.D., CableLabs; Zhensheng (Steve) Jia, Ph.D., CableLabs; L. Alberto Campos, Ph.D., CableLabs
The demands for increased capacity, speed, reliability, and coverage in access networks are ever-growing, driven by the proliferation of high-bandwidth applications and services. Passive optical networks (PON) play a crucial role in meeting these demands due to their efficiency and cost-effectiveness [1-3]. A PON is a point-to-multipoint optical network architecture that utilizes passive components in the field, forming an optical distribution network that supports multiple end-users effectively. This architecture is instrumental in delivering high-speed internet and other communication services, making it a backbone for modern optical access networks. Several generations of PON systems have been standardized through the efforts of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) and the IEEE 802.3 Ethernet Working Group [4-6]. These advancements highlight the continuous evolution and adaptation of PON technology to meet the growing demands of modern optical access networks.
As the industry progresses toward 100G capacity and beyond in PON, intensity-modulation directdetection (IM-DD) technology faces significant challenges due to its limited power budget, capacity, and susceptibility to fiber impairments. In contrast, coherent technology offers higher receiver sensitivity, supports advanced modulation formats, and provides a larger link budget, making it more suitable for future PON applications. Coherent optics, once limited to long-haul networks, are now expanding into short-haul and access networks, paving the way for future generation optical access networks.
In this work, we showcase the great potential of CPON technology in terms of cost reduction, flexibility, and survivability. By demonstrating key innovations such as low-cost ONU designs, efficient upstream burst processing, adaptive modulation, flexible data rates, and innovative protection schemes, we want to show how CPON can provide a robust and scalable solution for the next generation of optical access networks.