SHINHOP laser

According to the feedback information from SHINHOP Laser over the years regarding the after-sales service of battery cell laser welding equipment, many customers often inquire about the issue of switching between single-mode and multi-mode laser welding machines. They want to know if the fiber laser they are using can directly switch to multi-mode to try another mode for welding Others.
In fact, the answer is quite clear. Fiber lasers cannot switch between single-mode and multi-mode at any time during use, which also indicates that users do not yet understand fiber lasers. It can be said that single-mode and multi-mode are two different types of lasers. Depending on which mode of laser the user is using, a professional laser equipment company needs to configure it more scientifically for you. So what are the differences between single-mode and multi-mode? What do they actually mean?
The modules of fiber lasers are divided into single-mode and multi-mode. In cutting applications, the focused light spot has a significant impact on the quality of the cut. The core of a single-mode laser is relatively thin, and its beam quality is better than that of multi-mode, with energy distribution following a Gaussian distribution, where the energy density is highest in the center, and the three-dimensional graph resembles a sharp, round peak.

1. Different core diameters
1. Multi-mode: The core diameter of multi-mode fiber is typically 50μm or 62.5μm.
2. Single-mode: The core diameter of single-mode fiber is typically 9μm.
The core of multi-mode lasers is relatively thicker, and the beam quality is somewhat inferior to that of single-mode. The energy distribution is more uniform compared to single-mode light spots, and the three-dimensional image resembles an inverted cup, with the steepness of the edges being much steeper for multi-mode than for single-mode.
2. Different light sources
1. Multi-mode: Uses LED (Light Emitting Diode) or Vertical Cavity Surface Emitting Laser (VCSEL) as the light source, because LED light sources can produce many modes of light (the light is more dispersed).
2. Single-mode: Uses lasers or laser diodes as the light source, because laser light sources can produce a single mode of light, with advantages such as high brightness and high power.
3. Different dispersion
1. Multi-mode: The refractive index of multi-mode fiber is divided into gradient and step types.
2. Single-mode: The core of single-mode fiber is generally made of a single material, with a fixed refractive index.
5. Different costs
1. Single-mode fiber has a wide transmission bandwidth and long transmission distance, but it requires a laser source, making it more expensive.
2. Multi-mode fiber has a lower transmission speed and shorter distance, but its cost is relatively low.
6. Different numbers of transmission modes
1. Single-mode fiber has a small core diameter and dispersion, allowing only one mode of transmission.
2. Multi-mode fiber has a large core diameter and dispersion, allowing hundreds of modes of transmission.
7. Different wavelengths
The working wavelength of multi-mode optical modules is generally 850nm, while the working wavelength of single-mode optical modules is generally 1310nm or 1550nm.
The advantage of single-mode is in thin plates, while the advantage of multi-mode is in thick plates. There is no comparative value between single-mode and multi-mode; both are configurations of fiber lasers. It's like a car: a sedan is suitable for highways, while an SUV is suitable for off-road, but a sedan can also run on rough terrain, and an SUV can also run on highways. Therefore, whether to choose multi-mode or single-mode fiber lasers depends on the actual processing needs of the end customer.
So how should we choose between single-mode and multi-mode?

【↑↑↑↑Single-mode laser welding equipment commonly used for cell welding↑↑↑↑】
From the perspective of power levels, lasers below 3000W use single-mode, focusing on welding or cutting thinner workpieces, while high-power lasers often use multi-mode. Single-mode energy is more concentrated, while multi-mode energy distribution is more balanced. Therefore, the two modes are determined based on different needs, and there is no distinction between which mode is better or worse. At the same time, the core of single-mode is generally thinner, which means that the same power laser transmits through it, and the light energy carried by the single-mode core is greater, posing a challenge to the material. Additionally, when cutting high-reflective materials, the high-intensity reflected light and emitted laser overlap. If the tolerance of the fiber material is insufficient, it can easily "burn the core," which is also a challenge for the lifespan of the core material!
Therefore, many laser manufacturers still choose multi-mode configurations for high-power fiber lasers (above 5000W).
From the current situation of many battery cell manufacturers' welding products, the power of the lasers used is generally below 3000W, and using single-mode lasers can be considered a good choice. Of course, some users' process requirements may need to adopt multi-mode to complete welding. The two modes cannot be compared; everything is allocated according to demand, and there is no issue of which quality is better or worse.
【Finally】
Single-mode and multi-mode are independently distinct on their respective fiber lasers. As of now, there is still no functionality in the international market that allows switching modes on the same laser at any time, but we cannot deny that it may be achievable in the future. At least, it still requires the efforts and innovations of scientists worldwide.