Recently, China Telecom Research Institute (CTRI), together with ZTE Corporation and Yangtze Optical Fibre and Cable Joint Stock Limited Company (hereinafter referred to as "YOFC", stock code: 601869.SH, 06869.HK), has completed a large-capacity transmission experiment in S-, C- and L-bands using standard single-mode silica fibre. They achieved a peak rate of 1.2 Tbit/s on a single wavelength channel and surpassed 120 Tbit/s for one-way transmission on a single fibre, setting a new world record for real-time transmission rates over standard single-mode fibre. This achievement allows the transmission of hundreds of 4K HD movies or several AI model training datasets in a second.

This verification test of single-fibre one-way transmission exceeding 120 Tbit/s marked a breakthrough in the system's spectral width, key algorithms, and architecture design. Firstly, in addition to traditional C-band foundation, the system's spectral width has been extended to include S- and L-bands, achieving an ultra-wide communication bandwidth of up to 17 THz across S-, C- and L-bands, spanning from 1,483 nm to 1,627 nm. Secondly, in terms of key algorithms, CTRI proposed a scheme to maximize spectrum efficiency through adaptive matching of symbol rate, channel spacing, and modulation formats based on the fibre loss and power transfer characteristics in the S-, C- and L-bands. Moreover, leveraging ZTE's multi-band system filling wave and automatic power equalization technology, the channel-level service performance is balanced and the transmission distance is minimized. Finally, regarding architecture design, the cutting-edge co-packaged optics (CPO) technology is utilized for this real-time transmission. As a result, the baud rate of single-wave signals exceeds 130GBd, and the bit rate reaches 1.2Tbit/s, greatly reducing the number of optoelectronic components needed.

This experiment used the fibres developed by YOFC, featuring ultra-low attenuation and a large effective area. This fibre, with a reduced attenuation coefficient and larger effective area, helps to broaden the system's spectral width to the S-band, achieving a maximum real-time single-wave rate of 1.2 Tbit/s. Currently, the localization of this fibre has been achieved in terms of design, preparation, processing, and raw materials.

As artificial intelligence technology continues to advance and finds more business applications, the demand for data center interconnection bandwidth has surged. All-optical network, as the cornerstone of digital information infrastructure bandwidth, needs to further break through the rate and capacity of optical transmission. Adhering to the mission of "Smart Link Better Life", YOFC will cooperate with operator customers in the research and development of core and key technologies in optical communication. Together, we aim to engage in profound partnerships related to new rates, new bands, new fibres, and business explorations in these fields. Moreover, YOFC will establish new quality productive forces through technological innovation to continuously drive the sustainable development of all-optical network, thus laying a solid foundation for the digital future.