It's fascinating to think you can combine and split signals on the fly with prisms. It should be completely obvious but I've never thought about it, my mind is far too set into digital habits. By comparison electronics feel so slow.
It's the micron-precise alignment of the four beams that is astonishing. I can't see which part(s) is actively aligned to line up the beams.
Tom
Those are not prism. Prism implies it used as dispersion component, which is not the case. The thing does the real work there is the dichroic thin film coating on those prism shaped glass.
Yes. There are optical switches out in the market that use prisms to switch lambdas without any optical-electrical-optical conversion.