Exceeding the Nonlinear Shannon-Limit in Coherent Optical Communications by MIMO Machine Learning · HackerPapers discussionshttps://hackerpaper.kaipfister.de/p/1802.09120/Collected HN comments and submissions linking this paper.enMon, 02 Nov 2026 11:16:22 GMTExceeding the Nonlinear Shannon-Limit in Coherent Optical Communications by MIMO Machine Learning — mentioned by mmmBaconhttps://news.ycombinator.com/item?id=23186081urn:hackerpapers:mention:1802.09120:23186081Thu, 14 May 2020 21:58:49 GMT<p>It sounds like you are describing direct detect systems. These are no longer deployed in subsea. Due to the advent of coherent optical transmission and DSP, dispersion is no longer an issue for long distance optical communication. The limitation becomes nonlinear “crosstalk” between wavelengths and lower dispersion makes the nonlinear crosstalk worse as the phase matching condition for nonlinear processes can be reached more easily. To avoid this most new subsea cables use a high dispersion design as this helps mitigate nonlinear effects. Additionally coherent systems have a higher spectral…</p><p><a href="https://hackerpaper.kaipfister.de/p/1802.09120/">Paper and discussion history</a>. A mention is not an endorsement.</p>eess.SP