The difference between multimode and single mode of fiber laser—Winnie

As the power of fiber lasers continues to rise, fiber lasers have been scale up for industrial cutting. Due to its high beam quality, fiber lasers can achieve very small focal diameters and the resulting small slit widths are refreshing process standards in various fields.


Optical fibers can be classified into single mode fibers and multimode fibers depending on the modulus of the transmission point. By “mode”  meanS a beam of light entering the fiber at a certain angular velocity. A single-mode fiber uses a solid-state laser as a light source, and a multi-mode fiber uses a light-emitting diode as a light source.

The difference between multimode and single mode of fiber laser

In the cutting application, the focused spot has a great influence on the quality of the cut. The core of the single-mode laser is relatively thin, the beam quality is better than multimode, the energy distribution is Gaussian, the intermediate energy density is the highest, and the three-dimensional map is a sharp circle. The shape of the mountain.
The core of a multimode laser is coarser than that of a single mode. The energy distribution is smaller than that of a single mode. The three-dimensional image is an average of a single-mode spot. The three-dimensional image is an inverte cup. From the edge steepness, the multimode ratio The single mode is steep.


The 1mm thin plate cutting speed is 20% higher than the multimode, but from 2mm, the speed advantage is gradually reducing. Starting from 3mm, the advantages of high power multimode laser are obvious in both speed and effect.

Which is better?

Therefore, the advantage of single mode is thin plate, the advantage of multimode is thick plate, single mode and multimode are not compare with each other. They are all a configuration of fiber laser. It is like a car. The car is suitable for highway and off-road suitable for mountain. However, the car can also run the mountain, the off-road can also run the road, so the choice of multi-mode or single-mode fiber laser depends on the actual end-user processing needs.
The single-mode core is generally thin, meaning that the laser of the same power is transmitted in it, and the light energy carrying capacity of the single-mode core is larger, which is a test for materials. When cutting high-reflection materials, the high-intensity reflecte light and the emitted laser are superimposed. If the fiber material is not sufficiently tolerated, it will be very easy to “burn the core”. And it is also a challenge to the life of the core material.
From the perspective of power level discrimination, the laser of 1000W or less is mainly due to its low energy. And the thickness of the main processing material is toward the thin plate. Therefore, the single-mode configuration of the laser within 1KW is in line with the actual market conditions. From the perspective of the entire processing industry, the improvement of processing quality is a rigid requirement. Lasers with a power of more than 1KW should thin and thick, and cannot compromise. Therefore, many laser manufacturers still use multi-mode configurations in the configuration of high-power fiber lasers.