I was thinking the same thing -- this is what RF digital comms engineers have done for many decades. The cleverness of their technique appears to be the generation of a perfect "picket fence" of rectangular spectra in the frequency domain -- which inherently results in raised cosine pulses in the time domain. I have to agree with the comment from the researcher, that it's hard to believe nobody thought of this before.
If I read this correctly, the idea of shaping the optical symbols to cram as many symbols/sec as possible is what RF engineers have done for a long time. Using smooth shapes, a typical example being the "raised cosine curve," you can reduce the bandwidth of the medium, for any given data carrying capacity.
Increasing bandwidth with a transmitter change will be great for the industry. Not having to replace the optical medium could be an easy upgrade path for existing deployments. Thanks for the work and learning.
The Other Tesla David Blaza5 comments I find myself going to Kickstarter and Indiegogo on a regular basis these days because they have become real innovation marketplaces. As far as I'm concerned, this is where a lot of cool ...