Pulses are defined by various characteristic values. In addition to the pulse width or pulse duration, other characteristic values are the period duration, the pulse amplitude, the rise time and fall time, the duty cycle and some others.
These characteristic values apply equally to electrical and optical pulses. For the pulse duration itself there are different definitions. The most common definition of pulse width refers to the time of a pulse that lies between the 50-% values from the rising and falling pulse edges. The 50-% value, Full Width at Half Maximum( FWHM), refers to the maximum voltage value of the pulse. If there is a deviation from these specifications, it should be noted. Another definition uses the 90-% value, or 1/e, with e=2.718 of the maximum voltage value.
As for the pulse width of optical pulses, it can vary between milliseconds `(10^-3)` and attoseconds `(10^-18)`. Light modulation with an electro-optic modulator( EOM) can generate pulses in the range of picoseconds `(10^-12)` to pulses of any length. Similar values can be achieved with an acousto-optic modulator( AOM). Shorter pulse widths of femtoseconds `(10^-15)` are possible with mode-locked lasers.