As demand for bandwidth continues to increase and the need to reduce the cost of optical transport becomes more pressing, a new breed of coherent pluggable optics has emerged with 400G coherent pluggables. This generation leverages 7-nm CMOS technology and cutting-edge optoelectronics to deliver 400 Gb/s in pluggable form factors such as QSFP-DD and CFP2, thus redefining business and network economics by reducing power consumption, simplifying the network, and enhancing service flexibility, all of which contribute to a significant reduction in total cost of ownership. However, deploying coherent pluggables comes with its own set of challenges that need to be addressed to unlock their full potential. These challenges include:
- Deployment over single fiber such as in access networks (PON, 5G backhaul, etc.)
- Deployment over legacy infrastructure that consists of a mix of technologies and capabilities including cascaded ROADMs, 50 GHz fixed grid, etc.
- Lack of troubleshooting and automation tools
- Limited management when deployed in a host device other than a WDM platform
Adding Intelligence to Coherent Pluggables
A new breed of intelligent coherent pluggables, such as XR optics driven by the Open XR Optics Forum, has been introduced to the optical networking market to overcome the operational challenges mentioned above. They leverage digital subcarriers to enable higher optical performance; new optical configurations like point-to-multipoint, including a 4 x 100G coherent breakout; and new deployment models such as over single-fiber working. They also offer numerous optical transport features that for the longest time have been limited to fully featured optical transport platforms.
As previously stated, the operational challenges that coherent pluggables face today touch every aspect of the service delivery cycle. Therefore, in order to overcome these challenges, the new generation of coherent pluggables was designed and built around the principle of complete and remote software programmability. Key functions can be set through software to enable successful deployment and optimized performance over any given link in any given application. Programmable functions include mode (ZR, ZR+, XR), baud rate, spectrum, launch power, modulation, transmission fiber (single fiber or fiber pair), and traffic flows (asymmetrical, symmetrical). The combination of software programmability, embedded system-level features, and a new paradigm for management overcome current operational challenges, as follows:
- Enhanced optical performance by leveraging vertical integration and software-configurable building blocks for a significant reduction in CapEx/OpEx
- Easier management through support for the Open XR Optics Forum’s dual-management architecture, where coherent pluggables can be managed through the host device for basic configurations as well as independently of any router support for more sophisticated optical functions, such as point-to-multipoint configuration and operation over single fiber
Figure 1: Deployment over single-fiber working - Deployment over single-fiber working by leveraging digital subcarriers for downstream and upstream traffic flows (Figure 1)
- Seamless deployment over legacy infrastructure by leveraging software-configurable building blocks and selecting the right modulation, baud rate, launch power, spectrum width, and many other factors
- Streamlined operations through automation as intelligent coherent pluggables are equipped with secure and automated processes that accelerate turn-up and capacity allocation
So, What’s Next?
The evolution of coherent pluggable transceivers is set to take a significant leap forward with the introduction of 800G coherent pluggables, which are poised to complement the current 400G versions by providing a cost-effective and efficient optical transport solution for aggregated traffic and data center interconnect. These next-generation pluggables represent a transformative step in network technology, offering unprecedented performance and efficiency leveraging cutting-edge 3-nm-based CMOS technology and support for advanced features like open probabilistic constellation shaping and multi-vendor interoperability.
These 800G intelligent coherent pluggables are not just a mere upgrade in speed; they are a comprehensive enhancement that simplifies deployment across various network scenarios without compromising performance, visibility, or resilience. As the industry moves toward supporting native 800 GbE traffic protocols, these 800G pluggables are set to become the new standard, providing a robust solution for the future of high-speed broadband access and core transport applications. The key characteristics of emerging 800G intelligent coherent pluggables can be summarized as follows:
- Multi-bit-rate capacity at longer reaches: 800G intelligent coherent pluggables are not only about their maximum bit rate (i.e., 800G); they also enable lower bit rates to be transported over unprecedented distances, especially in compact form factors such as QSFP-DD. This includes 400G over 3,800 km, 600G over 3,000 km, and 800G over 2,000 km.
Figure 2: Multi-bit-rate capacity at longer reaches - Interoperability: 800G intelligent coherent pluggables are designed to meet and exceed 800G ZR and 400G ZR OIF standards and are interoperable with any OIF-compliant ZR transceiver. Moreover, they are designed to be multi-vendor interoperable through OpenROADM 6.0 for “open probabilistic shaping FEC” and compliant with OIF 800G ZR (tracking OIF 2021-144-15), OIF 400G ZR (Implementation Agreement 2.0), and OpenZR+ Rev 3.0. In bookended configurations, they exceed MSA performance in a very low power envelope.
- Integrated system-level features: 800G intelligent coherent pluggables are feature-packed with system-level capabilities including Layer 1 wire-speed AES-256 encryption with in-pluggable key management, streaming telemetry, and numerous remote troubleshooting and diagnostic tools, including remote loopbacks and demarcation points. Such system-level features help network operators quickly pinpoint and solve network issues.
- Easy deployment over legacy infrastructure: Just like their predecessors, 400G intelligent coherent pluggables, this next generation also leverages full programmability for seamless deployment over existing legacy infrastructure. By selecting the right modulation, launch power, and many other factors, network operators can maximize transmission capacity over the most challenging network configurations, including cascaded ROADMs.
Conclusion
Intelligent coherent pluggables are transforming network economics by cutting power usage, streamlining networks, and increasing service adaptability. The optical networking sector is poised for a significant shift with 800G intelligent coherent pluggables, setting new capacity and performance standards and propelling the industry toward a future of advanced connectivity.
For more information on what’s next in coherent pluggables, please visit https://www.infinera.com/innovation/icex-coherent-optical-pluggables/.
