In most systems, we use fixed pulse length. Depending on the fibre length and light quality we are limited in sending a certain amount of energy through an optical fibre. If we have a pulse of 1mj and 100 nanoseconds long, then we are sending 10 Kw through the fibre. A fibre can withstand a certain amount of energy and can behave non-linear if pushed to the limit. Therefore we could say the pulse duration is an important factor to consider on the engineering side. For the cleaning process, we can conclude: the shorter the puls length or duration the higher the energy shock on the surface and the less the thermal influence. on the surface. Oxides are not so sensitive to shorter pulse lengths but we prefer the non-re-oxidation effect of the shorter duration. For paints or organics, a longer pulslenght is more efficient to overcome the thermal isolation topic.  if to short, the energy is not enough transferred to the paint layer. Only for special applications do we need to consider the pulslenght as an important factor. Seen the fact the pulse duration has some big influence on fibre and optics and there overload risks it is better to have a fixed pulse duration instead of a variable one which could lead to errors.