Türk Telekom and ZTE Complete World’s First 1.6T DWDM Trial over 12 THz Spectrum on Live Network

As Türkiye's largest integrated telecom operator, Türk Telekom provides a comprehensive suite of services—spanning mobile, fixed, and data communications—to tens of millions of residential and business customers. With the booming global digital economy and the promotion of 5G network construction in Türkiye, building ultra-wide and ultra-high-speed optical network infrastructure has become a common goal for Turkish operators. In this evolving landscape, continuing to lead the development of advanced optical infrastructure to fully realize Türkiye’s potential as a strategic Eurasian hub has become a core priority for Türk Telekom.

In March 2025, ZTE and Türk Telekom jointly completed the 1.6 Tbps OTN trial with 12 THz bandwidth on the live network in Istanbul, Türkiye's largest city, achieving ultra-high-speed transmission of 400GE/800GE services. The success of this trial not only validates that ZTE's 12 THz Tbit OTN solution is the optimal choice for single-fiber capacity exceeding 100 Tbps, but also lays a solid foundation for Türkiye’s large-scale 5G deployment, industrial digital transformation, and economic growth across Eurasia.

High-Speed OTN Opens a New Era of Interconnection

The global digital transformation is driving exponential growth in international traffic. With the rise of scenarios such as lage AI model training, multinational intelligent manufacturing, and cloud-end collaborative R&D, the scale of global cross-border data flows is undergoing a structural leap. For instance, the single cross-border transmission of 100-billion-parameter large-model data exceeds 500 TB. The cross-border transmission of global AI training data is expected to increase by 30 times over the next two years, surpassing 10 EB per year by 2028. Additionally, the globalization of intelligent manufacturing drives industrial traffic to new heights, with leading enterprises averaging 2.5 PB of data transmission per month, an eightfold increase from 2020.

The ultra-high-speed growth of global traffic is driving the evolution of optical networks toward 400G and 800G capacity on a single wavelength. The spectrum width occupied by signals continues to expand. The traditional C++ band that can only carry 40-wavelength services is no longer sufficient to meet the growing requirements for single-fiber capacity. Expanding spectrum resources to the C+L bands (12 THz in total) has therefore become an inevitable choice for the global communications industry.

Collaborative Innovation to Set New Industry Boundaries

Türk Telekom and ZTE have maintained a deep, long-term partnership in ultra-high-speed optical networking. Building on the success of their 100G/B100G hybrid metro network—which won the "Best Mobile Transport Solution to Connect 5G Services" award at the 2022 5G MENA—the two companies achieved another milestone in March 2025 with the first 12 THz, 1.6 Tbps OTN live network trial in Istanbul.

Leveraging ZTE's flagship optical transmission product, the ZXONE 9700, this trial also utilizes ZTE's in-house developed 1.6 Tbps optical module, providing a single-fiber capacity of up to 96 Tbps and doubling the spectrum bandwidth of traditional solutions. The key optical-layer component, the wavelength selective switch (WSS), features integrated C+L band support, further optimizing costs and power consumption. In addition, any switching of the spectrum in the C+L band can be implemented, significantly improving the flexibility of the transmission system. Compared with the previous-generation 1.2 Tbps optical module, the 1.6 Tbps optical module used in this trial achieves a 25% reduction in power consumption per gigabit, effectively saving operational costs for Türk Telekom and supporting its strategic objective of developing a green and low-carbon optical network.

To verify the feasibility of the 1.6 Tbps solution for follow-up application in  commercial networks, the ZTE technical team and the Türk Telekom team conducted in-depth on-site discussions and systematically tested a wide range of planned commercial network scenarios. Special verification was performed on the ZTE 1.6 Tbps solution within the ultra-wide spectrum range of 6 THz (C) + 6 THz (L). The test items covered 400GE/800GE independent service access, hybrid service access, transmission stability, multi-span transmission, and external wavelengths. The final validation results showed that the solution was stable in all test scenarios, laying a solid foundation for subsequent large-scale deployment.

Win-Win Cooperation, Driving Türk Telekom’s Network Upgrade

Bearer networks lay the foundation for network construction. As a leader in the Turkish communications industry, Türk Telekom is committed to providing high-quality and seamless communications services to users in the region based on its profound technological expertise and continuous innovation. The successful verification of the 1.6 Tbps solution based on the C+L-band system will not only solidify its leadership in the local market, but also reinforce its image as a technological pioneer in the global arena. As the 1.6 Tbps solution matures, it will fully meet Türk Telekom's future demand for increased optical network bandwidth during 5G service development, effectively supporting service transmission between Europe and Asia, and significantly improving Türk Telecom's core competitiveness in the transnational communication services.  

As a pioneer in international transmission networks and a long-term strategic partner, ZTE will collaborate with Türk Telekom to explore the evolution of existing infrastructure based on this successful pilot. This partnership aims to build a next-generation "intelligent, efficient, and green" optical network, accelerating Türkiye's 5G development. Moving forward, they will drive the large-scale commercial deployment of the 1.6 Tbps solution, contributing practical insights to the global optical communications industry and catalyzing technological iteration to address the challenges of future traffic growth.