155x100Gbit/s coherent PDM-QPSK over 7200km transmission distance

: We report the transmission of 155 channels with 100Gbit/s PDM-QPSK modulation over 7200km of pure silica core fibre, exploiting hybrid Raman-EDFA amplification and digital coherent detection. A record 112Petabit/s·km capacity×distance product is demonstrated. Introduction Commercial undersea cables have been relying on wavelength division multiplexing (WDM) at 10Gbit/s channel rate for almost 10 years, but a new generation of cables is now in sight, using channels at 40Gbit/s. Recent research has shown how to further increase the capacity of ultra-long haul systems by 1,2 using 100Gbit/s per channel . In this work, we 2 extend previous results by employing a different fibre type, and combined C+L band amplification, supporting a total of 155 channels. An overall capacity of 15.5Tbit/s is sent into a single fibre over a 7200km distance. To the best of our knowledge, this is the first report of a capacity x distance product (CxD) in excess of 100Pbit/s·km. The CxD is often used to rank transmission experiments, by rating both the challenges of generating large flows of data and of making them propagate over very long distances. The CxD of the most impressive experiments reported over the last 12 years is depicted in Fig 1. A steady increase of CxD had been observed up the beginning of the millennium by using only direct detection. The introduction of balanced detection for recovering phase-modulated data helped to improve CxD by a significant, but limited, 40%. More recently, the association of coherent detection with powerful digital signal processing has pushed the best reported CxD's one step further.