The laser of the laser cutting machine is a special energy source. This type of laser has radiation to a certain extent. How much harm is this radiation? According to the different optical radiation of lasers, CDEH and IEC generally divide the hazard level of lasers and laser products into four levels, and the basis for their classification corresponds to the radiation limit AEL that can be handled, that is, AEL is the allowable radiation of lasers and laser products. AEL is related to wavelength and exposure time under radiation.

Level 1: Under normal operating conditions, there will be no harmful light radiation.

The second level: its radiation range is in the visible spectral region, and its AEL value is equivalent to the value when exposed to the radiation of the first level product for 0.25 seconds. This grade of product needs to be attached with warning marks for safety testing.

The third level: divided into 3a and 3b. Level 3a will not cause damage to the naked eye for people with normal avoidance response to strong light, but it will cause damage to the eyes for observation through lens instrument. Class 3b products include radiation in the range of 200 nm to 1000000 nm, which may cause accidental injury if viewed directly with naked eyes. Its management and control are stricter than the second level.

Level 4: AEL is above level 3, which will not only cause damage to human eyes when looking directly, but also cause external damage under other circumstances. Not only to eyes, but also to skin, and even cause fire. Such products shall be strictly managed and controlled.

According to the CDRH standard, for the optical fiber communication system using 1550nm laser and single-mode fiber, the output power of the first level product should be below 8.5mW, and the fourth level product should be greater than 500mW. According to IEC standards, for the optical fiber communication system using 1550nm laser and single-mode fiber, the output power of the first level product should be below 10mW, less than 50mW is level 3, and more than 500mW is level 4.

After the introduction of fiber amplifier in optical communication system, because the output power of fiber amplifier is greater than that of general semiconductor lasers, as a kind of laser products, the radiation safety of its use has also attracted everyone's attention. The International Telecommunication Union (ITU-T) also considered the safe use of lasers when formulating the standards for optical communication systems, especially those using optical fiber amplifiers (such as wavelength division multiplexing). In some recommendations, such as G.691, G.692, G.664, G.957, etc., the relevant definitions and descriptions of IEC825 were introduced.

Laser cutting machine is different from other ordinary light sources. The laser generated by laser can achieve the effect of energy concentration due to its monochromaticity, coherence, collimation and high energy density, thus causing damage to human organs (especially human eyes). For the laser in the infrared spectrum area, its damage to human body is mainly thermal effect, and for the laser in the blue and purple spectrum area, its damage is mainly photochemical effect. Therefore, when the human eye directly faces the laser emitted from the laser or optical fiber connector due to carelessness, it may cause injury to the eyes.