Laser safety
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Basics
Optical fiber telecommunication systems, their associated test sets, and similar
operating systems use semiconductor laser transmitters that emit infrared (IR) light at
wavelengths between approximately 800 nanometers and 1600 nanometers. The emitted
light is above the red end of the visible spectrum, which is normally not visible to the
human eye. Although radiant energy at near-IR wavelengths is officially designated
invisible, some people can see the shorter wavelength energy even at power levels
several orders of magnitude below any that have been shown to cause injury to the
eye.
Conventional lasers can produce an intense beam of monochromatic light. The term
monochromaticity means a single wavelength output of pure color that may be visible
or invisible to the eye. A conventional laser produces a small-size beam of light, and
because the beam size is small the power density (also called irradiance) is very high.
Consequently, lasers and laser products are subject to federal and applicable state
regulations as well as international standards for their safe operation.
A conventional laser beam expands very little over distance, or is said to be very well
collimated. Thus, conventional laser irradiance remains relatively constant over
distance. However, lasers used in lightwave systems have a large beam divergence,
typically 10 to 20 degrees. Here, irradiance obeys the inverse square law (doubling the
distance reduces the irradiance by a factor of 4) and rapidly decreases over distance.
System design
The
Metropolis
®
ADM (Universal shelf) system complies with the Food and Drug
Administration’s Center for Devices and Radiological Health (FDA/CDRH) regulations
FDA/CDRH 21 CFR 1040.10 and 1040.11 as a Class I and with IEC 60825-1 as a
Class 1 Optical Fiber Telecommunication laser product.
The system has been designed to ensure that the operating personnel is not endangered
by laser radiation during normal system operation. The safety measures specified in the
FDA/CDRH regulations and the international standards IEC 60825 and DIN/EN 60825
respectively are met.
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