Technological Prospection and Requirements of 800G Transmission Systems for Ultra-Long-Haul All-Optical Terrestrial Backbone Networks

With the standardizations of 400GE and 400G completed or near completion, the attention is now refocused to next generation techniques with larger bit rates, i.e., 800G. We can see that current research commonly aims to short-reach or metro transmission for sharing key components with 400G, while ultra-long-haul transmission (typically ≥ 1500 km) based on 800G is still in unknown state. Moreover, all-optical networking with OXC and ROADM is being gradually deployed all around the world, which further increases transmission performance requirement. According to past progress, it is urgent for us to analyze and clarify the requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. This work provides the technological prospection and requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. Firstly, the field network status and basic technical requirements for 800G are analyzed. Our record real-time 10-λ × 800-Gb/s sub-carrier-multiplexing 95-GBd DP PCS-64QAM transmission over 2018-km G.654.E Fiber with pure backward distributed Raman amplification shows that reusing the components of current 400G technique is not the future direction. By numerically simulating the transmission performances of non-fully-loaded and fully-loaded DWDM scenarios, symbol rate higher than 180GBd, G.654.E, and optical bandwidth ≥12 THz are necessary.