MOPA Fiber Laser Marking Machine For Color

In recent years,the pulsed fiber lasers marking is widely used for a variety of industries,At present,there are main two types:Q-switched & MOPA technology used in the pulsed fiber laser marker,MOPA as a more advanced laser technology.So,what is it?

In this article,we will introduce what is a MOPA laser,principle,advantage,application solution and what is the difference between Q-Switch and MOPA etc all information you may want to know.

What is a MOPA Laser

MOPA lasers are pulsed lasers with very high power outputs. MOPA stands for Master Oscillator with a Power Amplifier. The “MO” produces a highly coherent beam, and an optical “A” is used to boost the output power of the beam. The “MO” don’t need to be powerful nor high efficiency operate.Since the final efficiency is determined mainly by the “PA”. The combination of several laser amplifiers seeded by a common “MO” is essential concept of the High Power Laser Energy Research Facility.

How does a MOPA laser Work

The MOPA design posses two gas discharge chambers: the master oscillator and the power amplifier which can amplify seed light to reach the necessary power levels in a certain way. Its outstanding features are:Although seed light with a low energy in a tight spectrum produced by the master oscillator,However,when the light is passed through the second chamber(the power amplifier) which can amplify the light to reach the necessary power levels while preserving the main properties of the oscillator.Therefore,MOPA design with the ability to increase output power without changing the geometry, shape or operation principle,which combines the good pulse of the low-power seed light source(high beam quality) with high energy output advantages.

The MOPA structure light source chart:

It is mainly divided into two parts, the left box is a seed light source with high beam quality output, and the right box is a one or several-stage fiber amplifier device.

When will Choose a MOPA Laser

Although MOPA fiber laser has many advantages,but it is much more cost than Q-switch laser, usually we just choose a common fiber laser marking machine. Only select MOPA laser marking machine when require color marking on stainless steel and black marking on anodized aluminum.

Pros and Cons of a MOPA laser

You may often hear two parameters of laser marking machine:pulse duration and pulse frequency.What is it?Let us briefly explain it first.

Pulse duration refers to the duration of a single pulse,Therefore,it is measured in time unit,including milliseconds (ms), microseconds (us), nanoseconds (ns), picoseconds (ps), femtoseconds ( fs) and other magnitudes. The smaller the magnitude, the shorter the duration of pulse.

Frequency is the number of occurrences of a repeating event per unit of time. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.

The light of marking lasers is produced in pulses.In general, the pulse duration is fixed,range about between 80 and 120 ns. While pulse duration of MOPA laser is adjustable: range between 2 and 200 ns.

Compared to the Q-Switched laser, MOPA laser parameters pulse duration and pulse frequency can be variable independently what results in high flexibility.

For common laser marking machine,its frequency between 20 and 80 KHz,while MOPA laser maker between 1,6 kHz and 1000 KHz for MOPA laser.

Pros

• Pulse duration adjustable
• Large frequency range
• High flexibility
• Many material application

Cons

• More expensive than common fiber laser

What is Application of MOPA Laser

MOPA laser marking machine is suitable for the fine marking metal and non-metal materials, such as:black marking on the part of digital product, mobile phone keys, mobile phone shells, key panels, electronic components, oxidation, plastic marking, crafts and gifts etc.

MOPA laser marking machine is mainly used in color marking on stainless steel,black marking on aluminum oxid , anode stripping, coating stripping, semiconductor and electronics industries, plastic and other special materials marking and PVC plastic pipe industry.

MOPA Laser vs Q-Switch Fiber Laser

MOPA fiber laser as a new fiber laser. It can do all work what q-switch fiber laser can do. So what is the difference them? Why MOPA laser is much more expensive? What material can mark?Let us keep it.

Different technology

Although Both Q-Switch and MOPA laser marking machine use fiber technology and nearly have the similar appearance,but each use different fiber technology,here are some comparison of technology:

Gas discharge chambers

• MOPA:two
• Q-Switch:one

Pulse duration

• MOPA: Adjustable,range between 2 and 200ns
• Q-Switch:fixed,range about between 80 and 120ns

Frequency range

• MOPA: between 1,6 kHz and 1000 KHz
• Q-Switch:between 20 and 80 KHz

Different Material

Q-Switch fiber laser

Nickel,Carbon steel,Platinum,Tungsten,Gold,Aluminium,Carbide,

Silver,Titanium,Brass,PLA plastic,Silicon plastic,Chrome,Copper,Iron and other metals,Stainless Steel (Only white and dark colors),ABS plastic (high rate of melting burn),PC plastic (high rate of melting burn) and PBT plastic etc

MOPA

Gold,Aluminium (with dark color),Stainless Steel (with multiple colors),Platinum,Silver,Titanium,Brass,Tungsten ,Carbide,Nickel,Carbon steel,Chrome,Copper,Iron and other metals,ABS plastic (low rate of melting burn),PC plastic (low rate of melting burn),PLA plastic,Silicon plastic and PBT plastic etc.

Different Effect On Some Material

Metal deep marking

• Q-Switched:Rough shading
• MOPA:Fine shading

Transparent paint plastic buttons

• Q-Switched:Not easy to clean up
• MOPA:Easy to clean up, high efficiency

Electronics, semiconductor, ITO precision finishing

• Q-Switched:Very big Pulse width,Very strong energy
• MOPA: pulse width adjustable to make laser light spot more fine,energy adjustable and more even

Stainless steel black marking

• Q-Switched:Easy deformation & rough shading
• MOPA:NO deformation & fine shading

PC/ABS etc. Plastics

• Q-Switched:Marking edge yellow and rough
• MOPA:Without yellow color, smooth

Aluminium oxide thin sheet surface removal

• Q-Switched:Easy deformation & rough shading
• MOPA:NO deformation & fine shading

Anodized Aluminium black marking

• Q-Switched:None
• MOPA:different shades of black color can be done by setting up different parameters.

Summary

Compared to common fiber laser marker,the pulse duration and frequency of MOPA fiber laser are independently adjustable, and more large parameter range option,Therefore,MOPA laser marking is fine,it has  advantages that Q-switched fiber laser cannot in marking on aluminum oxide sheet, black marking on anodized aluminum blackening and color marking on stainless steel.

While the Q-switched fiber lasers poss more strong marking depth and better in deep engraving on metals, but the marking result is relatively rough.

In general, MOPA fiber lasers can almost replace Q-switched fiber lasers in laser high-end marking applications. In the future,with the development of MOPA fiber lasers,It will develop narrower pulse duration,higher frequency and higher power to meet the new requirements of laser application.