Fixed versus adjustable pulses
A Q-switched fiber laser emits pulses of roughly fixed duration, typically around 100 ns. A MOPA — master oscillator power amplifier — design lets the user set pulse width over a wide range and run at much higher repetition rates.
Why that matters
Short pulses put less heat into the part. On anodised aluminium this bleaches or darkens the layer without burning through, giving a true black mark. On stainless steel, controlled heating grows oxide layers that appear as colours.
Plastics
Shorter pulses also reduce foaming and burning on plastics, producing smoother, higher-contrast marks on housings and keypads.
When a standard source is enough
For engraving, deep marking and general coding on metal, a Q-switched laser is faster per unit of cost. Choose MOPA when the application calls for black anodised, colour, or delicate plastic marking.
