John Popelish wrote:

I wish I could, but this is the first I have heard of such
instrumentation. That is why I would like to read more about it.

Hopefully the poster mentioning the optical probe will explain a bit
more. But I recall seeing optically coupled instrumentation used in an
EMI screen room to couple signals in and out. To my knowledge, though,
the probes themselves were conventional, and fiber optics were used only
to replace connecting wires.

Roy Lewallen, W7EL