Re: A (potentially) astonishing step change in FO bandwidth. NOT
Here is why it won't magically increase fiber bandwidth 100-fold:
Photons have two polarization states, you can label them vertical/horizontal or (via a phase-shifted superposition of v/h) right-handed/left-handed. If you send "more complex / twisted polarization states", the light will interfere and you get a spatial pattern. What scientists in this field so ingeniously discuss is the spatial detection of light. Duh. You didn't realize that?
Now, if you have a multi-mode fiber, you can get multiple-modes of light through (spatial information, aka 'the mode', can get through the fiber). That has a price; let me quote from the first Google link that came up (https://www.quora.com/What-are-the-differences-between-single-mode-and-multi-mode-optical-fibers):
"The main drawback to the multi-mode cable, however, is that it loses strength over distance, therefore, is only useful in local networks traveling small distances.
- High attenuation and dispersion
- Greater data-transmitting capabilities
- Can be used within high-speed & large capacity networks
- Can still achieve much greater distances than coaxial cables"
So there is no magic :(.
(Disclaimer, I do not work with fibers and have no particular knowledge about them. I do, however, know my way around light and I can tell you with great confidence that there is no physically meaningful polarization state that cannot be described as superposition of h/v or right/left handed.)