Optical pulses are light pulses, they are flashes of light that are usually generated by lasers and transmitted with a laser beam. Due to the enormous bandwidth of optical transmission systems, optical pulses are extremely short. Their pulse duration is in the range of picoseconds (ps, `10^-12`) and femtoseconds (fs, `10^-15`).
The optical pulse durations result from bandwidth values in the terahertz range as supported by single mode fibers. The shortest optical pulses have a pulse duration of about 5 femtoseconds (fs). Due to the ultra-short pulse duration and extreme focusing, optical pulses can be used to generate high brightness, even those that have only moderate pulse energy. For example, a 10-fs pulse with an energy of only 10 milli-joules (mJ) has a peak power of 1 terawatt (TW).
The transmission of optical pulses in optical transmission systems is affected by the transmission media and the active and passive optical components. Optical pulses are subject to dispersion, attenuation, delay, nonlinear changes, and group delay. To ensure optimum and error-free transmission, these influencing factors must be compensated for as far as possible.