Super C+L: Smooth Evolution from Now to the Future
In recent years, new technologies and services — such as 5G, cloud computing, big data, IoT, 4K/8K, and AR/VR — have emerged. These result in an explosion of 5G traffic, with video accounting for a larger proportion of traffic and the demand for cloud computing remaining strong. Video and cloud have driven the need for transmission networks with larger capacity.
Three Challenges Facing Optical Transmission Networks
Demand for bandwidth keeps increasing. According to Omdia, optical network bandwidth doubles every 2.5 years. To achieve lower TCO, we must further reduce the per-bit cost. Currently, the coherent ultra-high-speed transmission rate is approaching the Shannon limit, and it is difficult to improve the fiber spectrum utilization. Therefore, wider spectrum is required.
The annual traffic growth rate ranges from 25% to 40%, yet the optical cables newly deployed each year is less than 10%. Clearly, the traffic growth rate far outpaces fiber construction speed. As such, we have no choice but to enhance single-fiber capacity to meet bandwidth requirements. To ensure lower latency and better experiences for MBB/FTTx and private line services, we need to enable one-hop transmission at the optical layer. To do this, we need WDM networks to support a longer transmission distance.
On the one hand, to achieve eco-friendly and low-carbon targets, optical transmission devices must have higher integration and lower power consumption. However, such traits degrade transmission performance, as we have seen in the evolution from MSA to CFP, CFP2, and QSFP. On the other hand, we demand high transmission performance to decrease relay devices, which is the key to reducing the TCO. Therefore, it is a challenge to balance integration and performance.
To help customers cope with the challenge, Huawei has launched industry-leading Super 200G/400G/800G and Super C+L band solutions. The two solutions improve the single-wavelength rate and single-fiber capacity while reducing the per-bit cost and power consumption, aiming to double capacity over the same transmission distance and achieve single-fiber 100T.
Increasing the single-wavelength rate brings more challenges. Huawei uses innovative materials to solve problems in high-speed modulation, optimizes link bandwidth based on optoelectronic packaging, and combines new modulation technologies with high-precision component algorithm compensation technologies to approach the Shannon limit.
Super 200G/400G/800G uses the cutting-edge channel-matched shaping (CMS) plus AI neuron algorithm to perform:
In 400G transmission with 100 GHz channel spacing, ultra-long-haul transmission over more than 1200 km can be commercially implemented based on G.652 fibers (without Raman), which is 20% longer than the industry average. After the transmission distance requirements of backbone networks in most countries are met, it is essential to improve spectral efficiency as this can further increase single-fiber capacity and reduce per-bit cost. In this regard, Huawei achieves single-wavelength 100 GHz, enabling 24T transmission capacity in C band and 48T in C+L band. Huawei’s 800G solution has an even higher spectrum efficiency, boosting overall capacity to 30% higher than the industry average.
Huawei’s 200G+ market share ranks first worldwide. Huawei has deployed over 20 commercial 800G pilot sites around the world and completed the industry’s longest 1100 km ultra-long-haul transmission test on 800G live networks.
Super C+L Band
In addition to improving the single-wavelength rate, increasing the available spectrum of fibers is another direction for enhancing fiber capacity. Compared to the traditional C band, Huawei’s Super C band solution for large-scale commercial use expands available spectrum by 25%. The C+L band is the main development direction for improving the available single-fiber spectrum. However, L band deployment faces challenges such as achieving flexible and on-demand coverage of hot links and optical power equalization due to stimulated Raman scattering (SRS).
With its technical knowledge and large-scale commercial applications in Super C band, Huawei has strong E2E Super C+L band solution capabilities in the following aspects:
To provide better commercial deployment of Super C+L band, Huawei uses pluggable OAs to perform on-demand deployment and smooth evolution to protect investments. To resolve the optical power equalization issue caused by SRS, Huawei has developed a Super C+L band orchestrator that enables μs-level detection and monitoring based on dedicated hardware, ensuring uninterrupted services during wavelength adding or dropping in C+L band.
Huawei will continue to explore 800G+ ultra-high-speed transmission technologies, research modulation algorithms and optical components with higher baud rates to achieve higher single-wavelength rates and performance, and strive to complete the first single-wavelength 1.6T test on live networks.
With Huawei’s advanced Super 200G/400G/800G and Super C+L band solutions, single-fiber 100T is within reach.
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