As it's common practice, each new hacker event needs something weird and funky. For this years summer camp in the Netherlands called WHY2025, we build a 400G link over a single fibre. Since 400G BiDi does not exist (yet), we had to get creative and built something, which might be considered out of spec.
Licensed to the public under http://creativecommons.org/licenses/by/4.0
about this event: https://pretalx.com/denog17/talk/KLXJS8/