Circuit to generate few microvolt pulse signal from volts pulse signal
If you make a resistor potential divider using a 1 kohm and a 0.1 ohm resistor you can convert a pulse of peak amplitude 1 volts to an output pulse of peak amplitude of 100 uV. Instead, if you used a 10 kohm resistor your output amplitude peak would be 10 uV. If you want a 1 uV output pulse use a 100 kohm resistor and 0.1 ohms.

If you need variations of these make several - they can all operate parallel driven together because the input impedance is in the region of tens or hundreds of kohm. The output impedance is very low (circa 0.1 ohm).

Don't use an op-amp for this - it will only disappoint unless you are prepared to pay tens of dollars or GB pounds.