China Telecom Research Institute recently teamed up with ZTE Corporation and Yangtze Optical Fibre and Cable Joint Stock Limited Company (YOFC), to complete an S+C+L multi-band high-capacity transmission experiment utilizing standard single-mode quartz optical fibre. The experiment achieved a maximum real-time single-wavelength rate of 1.2Tbit/s, resulting in a single optical fibre single-direction transmission rate exceeding 120Tbit/s. This marks a new world record for the real-time transmission rate via standard single-mode optical fibre, equivalent to supporting the streaming of hundreds of 4K HD movies or several AI model training datasets per second. The verification test has set new benchmarks in system bandwidth, algorithms, and architecture: Enhanced bandwidth: The traditional C-band spectrum expands to include the S and L bands, achieving a substantial communication bandwidth of 17THz across the S+C+L multiband, spanning the range of 1,483nm-1,627nm.

Higher performing algorithms: China Telecom Research Institute leverages the optical fiber loss and power transfer characteristics of the S/C/L bands, implementing a technique that maximizes spectrum efficiency through adaptive matching of symbol rate, channel spacing, and modulation code type. Additionally, with ZTE's advanced multi-band system filler wave and automatic power balancing technology, the service performance across all channels is balanced, vastly expanding the maximum transmission distance. Reimagined architectural design: this real-time transmission methodology incorporates the industry's leading CPO (Co-Packaged Optics) technology, boasting a single-wave signal baud rate exceeding 130GBd and a bit rate of 1.2Tbit/s, significantly reducing the number of required photoelectric components.

The experiment employs the ultra-low attenuation, large effective area optical fibre developed by YOFC. This fibre boasts a lower attenuation coefficient and an expanded effective area, facilitating the expansion of the system's bandwidth to include the S-band. This advancement enables the achievement of a maximum real-time single-wavelength rate of 1.2Tbit/s.