Technical advantages of fiber lasers
One of the main advantages of ytterbium-doped fiber lasers is that the 1070 nm wavelength emitted by the near-infrared laser is sufficiently close to the 1064 nm wavelength of the Nd:YAG laser, and there is almost no difference in the actual processing of laser marking. Therefore, the use of fiber lasers can relatively easily replace the continuous wave Nd:YAG lasers used in most marking applications. This early success led the marking industry to adopt fiber lasers and to learn more about the other advantages of this new type of laser. Therefore, people develop more advanced applications later, and fiber lasers can even challenge the relatively new diode-pumped solid-state laser technology. Fiber laser has an unrecognized aspect, that is, the entire optical path of the laser is completely maintained and tightly enclosed within a zero-loss all-clad fiber. Through advanced fiber splicing technology, all fiber-based optical components are combined to form a continuous optical path. This method has huge advantages. Unlike any other laser technology, there is no optical misalignment until the laser beam is output from the optical fiber and enters the focused optical path. Another related aspect is that, in principle, it is very simple to generate a higher average power; people can easily use longer activation fibers, or additional fiber amplifier stages and more pump diodes. Fixed or variable pulse length nanosecond fiber lasers. Fixed and variable pulse length nanosecond lasers have been widely used in laser marking. As we have seen, fixed pulse length fiber lasers are simple, robust and cost-effective. Strong market potential. However, under certain conditions, short laser pulses are more flexible and advantageous. In the field of laser marking, a typical example is marking transparent polycarbonate elements. This marking method is different from other materials in that smaller microbubbles are generated below the surface of the material, which appear black to the naked eye. Reduce the pulse length to 30 ns, and carefully control other marking parameters, such as speed, pulse energy and the distance between the filling line, micro-bubbles will be formed under the surface, and will not damage the surface of the component due to coalescence. The marking of medical equipment is in great demand in this way, because it can eliminate unnecessary trapped impurities. The use of pulses as low as 1.5 ns or even shorter has the advantages of some very special marking processes. Again, fiber lasers have huge advantages, because they can achieve short pulses and high pulse repetition rates, and have little effect on average power. For example, a leading supplier offers a special model fiber laser that can provide an average power of 18 watts at 300 kHz, a pulse of 1.5 ns (60 μJ), an M2 of 1.3, and a peak power of>40 kW. Although pulse width is an important parameter in laser processing, it is only one of many factors that affect the size of processed graphics. This combination of parameters allows infrared fiber lasers and traditional optical devices to jointly determine the size of the marking features, but previously it was only possible to use more complex and expensive short-wavelength diode-pumped solid-state lasers.