Level 1: Optical radiation that is not harmful to humans under normal operating conditions.
Level 2: It emits radiation in the visible spectral region and has an AEL equal to the value that would result from exposure to radiation from a Level 1 product for 0.25 seconds. Products in this class require additional warning labels for safety testing.
The third level: divided into two levels, 3a and 3b. 3a level is not harmful to the naked eye for people with a normal avoidance response to bright light, but it can be harmful to the human eye for observation through the use of lenticular instruments. 3b level products include radiation in the range of 200 nm to 1,000,000 nm, which can cause accidental injury if viewed directly with the naked eye. injury. The management and control of them are stricter than those of Level 2.
Level 4: AELs above Level 3 will not only cause damage to the human eye when viewed directly, but will also cause damage in other situations. Not only to the eyes, but also may hurt the skin, and even cause fire. Strict management and control of such products is required.
According to CDRH standards, for fiber optic communication systems using 1550nm lasers and single-mode fibers, the output power of Level 1 products should be less than 8.5mW, and greater than 500mW is Level 4. According to IEC standards, for fiber optic communication systems using 1550nm lasers and single-mode fibers, the output power of the first stage of the product should be less than 10mW, less than 50mW is level 3, and more than 500mW is level 4.
After the introduction of fiber amplifiers in optical communication systems, as the output power of fiber amplifiers is greater than that of general semiconductor lasers, as a laser product, the radiation safety of its use has also been a concern. The International Telecommunication Union (ITU-T) has also considered the safe use of lasers when formulating standards for optical communication systems, especially those using fiber amplifiers (e.g., wavelength-division multiplexing), and has introduced the relevant definitions and descriptions of IEC825 in some of its recommendations, such as G.691, G.692, G.664, and G.957, among others.
Laser cutting machines are different from other common light sources in that the laser produced by the laser is more capable of achieving energy concentration due to its monochromaticity, coherence, collimation, and high energy density, which can be harmful to the human organs (especially the human eye). For lasers in the infrared spectral region, the damage to the human body is mainly thermal, and for lasers in the blue and violet spectral regions, the damage is mainly photochemical. Therefore, when the human eye is accidentally exposed to laser light emitted directly from a laser or fiber optic connector, it can cause eye damage. In the case of ultraviolet lasers, this can lead to corneal inflammation and cataracts. For the current use of 1550nm lasers, laser marking machine light source in the far-infrared band, which is mainly on the cornea and eye crystal damage.