The mainly difference is the pulse width and frequency.

MOPA,the pulse width can be adjusted,its from 2ns to 250ns,but fiber laser can not.
MOPA,the frequency is from 0KHZ to 400KHZ,but fiber is 20-80KHZ.

Maybe its a little hard to understand these parameters.
So according to the marking effect,the difference is;

MOPA can mark different color on stainless steel,like green,blue,red,etc.But fiber just black and white.
MOPA is special to mark Oxidized Aluminum,like iPhone case,the IMEI number,but fiber can not.

For MOPA,there are only 20w and 30w.
For Fiber,there are 20w,30w and 50w.

MOPA can do all the marking of Fiber laser.(Except the deep engraving,cause just 20w,30w,the power is not enough)So as you required,you need MOPA laser for color marking,you need to focus on the condition,MOPA laser just can mark color on stainless steel.

Sharing the samples with you:

Usually,50w is suitable for deep engraving,and cutting thin silver gold,brass.
MOPA can not,cause 20w and 30w ,the laser power is not enough.

Of you are in the field of firearms engraving,most customers choose 50w Fiber laser.

Sharing one video by 50w:

 If you have more questions,just contact us:

Email:xintian111@xtlaser.com

Whatsapp:+8618253165863