"I've theorized that Dense Wavelength Division Multiplexing might increase interstellar communications bitrate beyond 20 kbps, perhaps as high as 800 Mbps. It's also possible that I don't have any idea what I am talking about."

I'll eagerly put $100 on statement #2.
You've written about a dozen posts demonstrating that you are totally clueless about lasers for optical interstellar communication despite being supplied with several URLs referencing how wrong your inept calculations were. Here's yet another clue. 64 DWDM channels is nothing. There are orders of magnitude more channels soon to be available. The announcement you cited gets beaten by multiple factors every 6 months.

-p (so little time, so may clues)