Blue Laser vs. Fiber Laser: A New Blue Ocean Market?

What is a Blue Laser?

Blue lasers refer to lasers with a wavelength range of 400 nm to 500 nm and emit blue light. Blue lasers possess characteristics such as short wavelength, low diffraction effect, and high energy, making them highly applicable in material processing, optical information storage, display technology, communication technology, and laser medicine.

diode laser engraving wood

Advantages of Blue Lasers

A shorter wavelength implies higher photon energy, which enhances the material's absorption rate of the laser. As shown in the figure, compared to the fiber lasers commonly used in industrial processing, the absorption rate of metal materials at 450nm increases by 10-60%, especially for high-reflectance metals like copper and gold. The energy consumption required for welding copper with blue lasers is 84% lower than that of infrared lasers, and even lower by 92% for gold. This means that while infrared lasers require 10 kW of laser power to weld copper or gold, blue lasers only need about 1 kW or 0.5 kW.

Blue Laser vs. Fiber Laser 01

Blue laser performance advantages stem from fundamental physical principles

Comparison of blue light laser and fiber laser welding

Semiconductor lasers based on gallium nitride material can directly produce 450nm wavelength lasers without further frequency doubling, thus having higher energy conversion efficiency.

Also, blue light absorbs less in seawater, allowing for longer transmission ranges, making it realistic to explore underwater laser material processing. Additionally, blue light can be easily converted to white light, enabling the compact realization of floodlights and other lighting applications.

Overall, blue lasers increase welding speed, which directly translates to faster production efficiency and minimizes production downtime. The consistency in welding quality significantly improves the production yield; the unique advantages of high-quality welds without spatter and porosity, higher mechanical strength, and lower electrical resistance broaden the range of processes. Moreover, blue lasers can perform conduction welding mode, which is unachievable by near-infrared lasers.

Development of Blue Lasers

Red and green lasers are widely used and have been industrialized for a long time. In contrast, blue lasers, affected by materials, cost, and technology, started later and have developed more slowly.

In 2015, the German semiconductor laser manufacturer DILAS launched a 450nm blue semiconductor laser system with a maximum output power of 25W, using fiber core diameters of 200μm or 400μm, expandable to 100W for material processing. In the same year, Shimadzu Corporation of Japan announced the successful development of a fiber-coupled high-brightness blue direct diode laser "BLUE IMPACT," using blue gallium nitride semiconductor lasers, the world's first commercialized laser source for laser processing.

Early blue lasers had low power and were not directly used in industrial processing, receiving little attention. However, in recent years, as blue TO package single-tube marketization, price reduction, power increase, and various industrial manufacturing and fiber coupling technologies continue to enrich, the feasibility of developing high-power blue lasers has been realized. For example, the German company Laserline achieved 2000W 600μm NA0.22 and 800W 400μm NA0.22 fiber-coupled output based on semiconductor stack spatial light shaping technology. The American company NUBURU achieved 1500W 105μm NA0.22 fiber-coupled output based on VBG dense spectral beam combining. The domestic company Lianying also launched a 1000W 800μm NA0.22 blue laser. The laser mentioned in the video above was launched by Kepler in January 2021, a blue 1000W 330μm NA0.22 product.

To enhance the reliability of kilowatt-level blue semiconductor light source systems, match automated coupling and alignment equipment, and compact product structure, Kepler used fiber combiners for power expansion. Moreover, each single module used for fiber combining contains multiple sub-units. Since blue laser chips are extremely sensitive to environmental conditions, to prolong the life of blue laser products, Kepler treated each sub-unit specially, effectively ensuring long-term reliability of the light source.

Kepler's unique packaging technology ensures the blue laser engraver products have high power stability, long life, and good reliability.

Besides the special chip protection design, Kepler's blue laser sub-units also feature a compact optical path design, beneficial for shortening the light path and enhancing the energy proportion within 0.15/0.22NA during fiber-coupled output, ensuring higher power enters finer fibers, thereby improving the overall system's beam quality and reliability of beam combining.

From the video mentioned above, we can observe that the welding process produces stable, bright weld surfaces without any spatter; under a 40X microscope, no porosity was found inside the weld.

As technology matures, the demand for high-brightness blue light sources in future high-end equipment manufacturing will be considerable and play a vital role. Kepler will continue to delve deep, providing customers with professional, high-quality services and advanced, reliable products, tirelessly striving to promote the development of China's laser industry.