The need for this arose while investigating an ESD susceptibility problem on a datalogger. Using conventional probes into the system it was impossible to find how the disturbance was propagating through the circuits as the probes picked up spikes even if they were shorted. The problem was the common mode transients present on the ground of the system, the probes just could not handle them.
A solution was found to use optical fibres to transmit the signal from an active probe back to the oscilloscope. With no electrical connection from the system under test, there was no common mode problem, nor was there any disturbance to the test conditions of the system.
The probe was further developed to offer:
The technology is licensed to a major DSO manufacturer.