Recently, during the 43rd US Optical Fiber Communication Exhibition and Conference (OFC), ZTE, OFS and NeoPhotonics jointly announced that the three parties will use the 66GBaud PDM-16QAM 400Gb/s WDM signal in the 75GHz channel and 100km optical relay span. The segment successfully transmitted over 6000km, breaking the record of 400G ultra-long-distance terrestrial high-speed transmission distance, and once again setting a new benchmark for ultra-100G ultra-long-distance transmission in the global optical network industry.This experimental system adopts the latest technology and device achievements of the three parties, including the high-sensitivity probability shaping coherent communication technology developed by ZTE, the low-power and small-volume high-bandwidth coherent driver modulator (HB-CDM) module designed and manufactured by NeoPhotonics, and OFS Corporation of large-aperture, low-loss TeraWave™ fibers.In this test, the probability shaped 506Gb/s PDM-16 QAM signal was transmitted over 6000 km with 75 GHz channel spacing over the OFS 100 km span.This is the longest wavelength division transmission distance of the current PDM-16QAM signal based on the terrestrial transmission system (100km span), and its line spectral efficiency exceeds 5.3b/s/Hz.The results will be used to develop and support new technologies for next-generation transport standards to address the exponential growth in IP traffic.Dr. Yu Jianjun, an optical communication scientist of ZTE Corporation and a fellow of OSA, said, "Single optical carrier 400G transmission has become the most attractive super-100G solution, which helps to reduce system complexity and bit cost, that is, with the minimum number of channels and the lowest cost. The number of sub-carriers, the minimum number of optical components and the simplest system architecture provide the highest transmission bandwidth, and reducing the number of optical components can usually reduce the cost of optical transceivers, thereby reducing the CAPEX of the entire system. ZTE has carried out 400G transmission technology. Long-term research has solved a large number of key technical problems, and the probability shaping technology used in this experiment has extended the transmission distance by about 40%."ZTE has been committed to providing important R&D resources for 400G/1T and above technologies, and has achieved a number of key innovations in this field.In 2012, ZTE released a 400G/1T DWDM prototype, providing seven solutions for various network applications.In the same year, ZTE and Deutsche Telekom jointly completed 100G/400G/1T ultra-long-distance hybrid transmission of 2,450 kilometers, setting a new record for high-speed signal hybrid transmission in the industry.In 2013, ZTE transmitted 400Gb/s data signaling over 5,000 kilometers, colluding with 25 ROADM nodes without electrical relays.In 2014, ZTE successfully transmitted 20 channels of 400Gb/s PDM-QPSK signals over 3,600 kilometers through standard single-mode fiber when the spectral efficiency was increased to 4b/s/Hz.In 2015, ZTE and OFS announced a new record of 400G ultra-long-distance high-speed transmission, and successfully transmitted 128.8-GBaud QPSK wavelength division signals for 10,130 and 6,078 kilometers through terrestrial optical fiber links.In 2016, ZTE transmitted 120Gaud 16QAM WDM signals over 1,200 kilometers through terrestrial optical fiber links, setting a new record for 800G transmission.In 2017, ZTE used enhanced advanced algorithms to transmit wavelength division signals over 2,125 kilometers over standard single-mode fiber links, successfully setting a record for 400G 8QAM signal transmission.In the field of 400G/1T, ZTE has submitted dozens of patent proposals, involving optical modulators, framers, оƬ and algorithms, etc., and has become a world-leading innovator in the field of high-speed optical communication technology.