It's funny to see this show up now. Optical-domain switching was a hot area of research in the early 2000s (e.g. [1]); it largely petered out as it became clear that digital-domain switching was more practical (because it didn't rely on exotic technology, and provided time for hardware to perform routing operations).
[1]: https://www.laserfocusworld.com/optics/article/16556781/many...