Next-Generation Optical Access Networks

- Overview

Optical fiber network technology is regarded as the cornerstone of the next generation of communication in modern society. Among several key parts of the optical communication physical infrastructure, the optical access network plays an important role in the end-to-end broadband network connection. 

The next-generation optical access network is expected to provide ultra-high-bandwidth services with ultra-large capacity, lower latency, higher reliability, and better security to support various ultra-high-bandwidth applications such as cloud/edge networks and 8K video streaming services, and the upcoming 3D holographic communication and digital replica of the physical world. 

In addition, optical access networks are playing an increasingly important role in mobile networks and will become more prominent in 5G/6G due to their requirements for bandwidth, coverage, synchronization and low latency. 

The success of future mobile networks will not only depend on new radio access technologies. The deployment of future wireless technologies will depend on the ability of optical access networks to seamlessly connect with radio access network (RAN) and edge/cloud computing resources. 

Combining the advantages of optical access technology and wireless access technology into a unified converged platform will help telecom service providers reduce network complexity, reduce operating costs, improve service quality, allocate resources optimally across different access technologies, and serve as a springboard for new business. 

A number of technologies are currently being developed for optical network convergence and access to increase throughput, improve energy efficiency, and simplify network design, deployment, and operations.

- Fiber QKD

Today's communication networks make extensive use of optical fibers to transmit data. It is therefore crucial to consider how to make this fiber-based communication quantum-safe as the quantum age dawns. Fortunately, quantum key distribution (QKD) is well-suited for fiber-optic platforms because fiber optics are ideal carriers for the single-photon signals that QKD relies on. 

However, researchers are also actively addressing many challenges to develop high-performance QKD systems that can be seamlessly integrated into current fiber optic networks around the world. 

Major research topics in the field of optical fiber QKD include:

• Twin-Field QKD & Other Novel QKD Protocols
• Quantum Networking
• Integrating Quantum & Classical Networks
• QKD Field Trials

- Quantum-secured Gigabit Optical Access Networks

An optical access network connects multiple endpoints to a common network node through a shared fiber optic infrastructure. They will play a vital role in expanding the number of users of quantum key distribution (QKD) networks. 

However, the presence of power dividers in commonly used passive network architectures makes the successful transmission of weak quantum signals challenging. This is especially true if the QKD and data signals are multiplexed in a passive network. The splitter introduces an imbalance between the quantum signal and Raman noise, which completely prevents recovery of the quantum signal. 

A method was developed to overcome this limitation and demonstrate the coexistence of multi-user QKD with full-power data traffic from a Gigabit Passive Optical Network (GPON). The dual feeder implementation is compatible with standard GPON architectures and can support up to 128 subscribers, highlighting how quantum-secured GPON networks may become commonplace in the future.

- Research Topics 

• Optical metro edge and access aggregation convergence
• Convergence of optical access and mobile broadband systems for new radio access networks
• Evolution of passive optical network (PON) for 50G and 100G data rate, and/or high split ratio and extended reach
• New fiber-wireless integrated radio access network architecture design and system interface
• New use cases and standards development for next-generation PONs
• New use cases for converged optical and wireless access networks
• Future softwarization and virtualization of optical access networks
• Applications of AI/ML in performance improvement and network telemetry in optical and radio access networks
• New advancements in improving the latency, reliability, protection, and security of optical access networks
• Dynamic bandwidth allocation (DBA) algorithms and multiple media access control (MAC) mechanisms
• Software-defined access and network slicing
• PON architectures for low latency and high-capacity mesh interconnect of edge nodes
• Techno-economics of analysis of optical access enabling dense 5G and beyond deployments