These transmission results, once again, set a benchmark for the global optical networking industry and support the next generation of transport standards to cope with the exponential growth of IP traffic.
The successful test demonstrated the coherent transmission system, based on the highest electrical time division multiplexing (ETDM) ratio of 128.8 GBaud over a record distance, in which 515.2 Gb/s polarization division multiplexing (PDM)-QPSK/9-QAM signals were transmitted over 10,130 km / 6,078 km, respectively, over a 100 km span of Terawave™ OFS optical fiber with optimized effective area and low loss. This was the highest ETDM-based symbol rate recorded to date, and the longest WDM transmission distance for single-carrier 400G signals over terrestrial span lengths (100 km).
For the first time, single-carrier 515.2-Gb/s PDM-QPSK signals on a 200-GHz grid have been successfully transmitted over distances exceeding 10,000 km in a terrestrial transmission environment. Researchers have also demonstrated the transmission of single-carrier 128.8-GBaud filtered QPSK signals on a 100-GHz grid over 6,078 km, using a SE line of 5.152 bps/Hz.
This result sets a new record for 400G transmission in both symbol rate and distance. The achievement, recently published in Optics Express (OSA), surpasses last year's record of 110 GBaud over 3,000 km of 400G transmission distance set by the same ZTE group.
According to Dr. Jianjun Yu, Chief Scientist for High-Speed Optical Transmission at ZTE and OSA Fellow, “ZTE’s single-carrier transmission emerged as an attractive solution because it offered advantages in terms of system complexity. Specifically, by employing the highest feasible electronic multiplexing rates with a minimal number of channel subcarriers, it reduces the number of deployed optical components, which typically dominate the transponder cost. ZTE has been relentless in driving research and development of 400G single-carrier transmissions into the future, and we have resolved most of the key technologies for this 400G product.”
According to Robert Lingle, Jr., Director of Systems Strategy and Technology at OFS, “Field-deployed Terawave™ fiber splicing and cable loss data have demonstrated the viability of large effective area fibers. The use of large areas of low-loss fiber is now widely regarded as a key tactic for improving range and spectral efficiency with advanced coherent transport modulation formats, in conjunction with both erbium and Raman amplifiers.”
