Laser apparatus using optical fibers for stable laser welding, and laser welding method using same

A laser device for stable laser welding, the laser device comprising:

• a first laser light source for irradiating a first laser beam with a first wavelength band of 1030 to 1090 nm in a direction in which an object is located;
• a second laser light source for irradiating a second laser beam with a second wavelength band of 400 to 480 nm or 800 to 980 nm in a direction in which the object is located;
• a combiner comprising a plurality of beam coupling optical fibers, the combiner for combining the first laser light source and the second laser light source so that the first laser beam is formed as a central beam, and the second laser beam is formed as an outer beam in an outer area within a preset radius based on the center beam so as to be combined into a hybrid ring mode laser beam;
• and
• a delivery optical fiber for delivering the hybrid ring mode laser beam output from the combiner in a direction in which the object is located,
• wherein the delivery optical fiber comprises a core part, a first clad, a second clad, a third clad, an interlayer formed between the core part and the first clad, and acrylic coating layer;
• wherein a diameter of the core part is 50 μm or less, a diameter of the interlayer is 50 to 70 μm, a diameter of the first clad is 70 to 400 μm, a diameter of the second clad is 440 μm, a diameter of the third clad is 500 μm, and a diameter of the acrylic coating layer is 550 μm;
• wherein a difference in refractive index between the core part and the first clad of the delivery optical fiber is 0.00145 or less, a difference in refractive index between the first clad and the second clad is 0.0167 or less, a difference in refractive index between the second clad and the third clad is 0.0578 or less, a difference in refractive index between the core and the interlayer is 0.0167 or more, and a difference in refractive index between the interlayer and the first clad is 0.0167 or less;
• and
• wherein numerical aperture (NA) between the first clad and the second clad is 0.22, and NA between the first clad and the third clad is 0.46.