Quantitative electro-optic measurements of ultrafast electrical signals on planar transmission lines: Pitfalls and caveats

We study electro-optic sampling for the quantitative detection of ultrafast electrical pulses propagating on planar transmission lines. The electro-optic signal strongly depends on the modulation frequency necessary for the lock-in detection. Yet, even when taking this frequency dependence into account it is not possible to simply “calibrate” the experimental setup using a well-known reference signal. Instead it is necessary to accurate determine the electro-optic transfer function of the experimental setup, which is a tedious task and might lead to very large uncertainties.