Alcatel-Lucent 1643 AMS Applications And Planning Manual page 19

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above 1400 nm cause corneal and skin burns, but do not affect the retina. The
thresholds for injury at wavelengths greater than 1400 nm are significantly higher than
for wavelengths in the retinal hazard region.
Classification of Lasers
Manufacturers of lasers and laser products in the U.S. are regulated by the Food and
Drug Administration's Center for Devices and Radiological Health (FDA/CDRH) under
21 CFR 1040. These regulations require manufacturers to certify each laser or laser
product as belonging to one of four major Classes: I, II, lla, IlIa, lllb, or IV. The
International Electro-technical Commission is an international standards body that
writes laser safety standards under IEC-60825. Classification schemes are similar with
Classes divided into Classes 1, 1M, 2, 2M, 3R, 3B, and 4. Lasers are classified
according to the accessible emission limits and their potential for causing injury.
Optical fiber telecommunication systems are generally classified as Class I/1 because,
under normal operating conditions, all energized laser transmitting circuit packs are
terminated on optical fibers which enclose the laser energy with the fiber sheath
forming a protective housing. Also, a protective housing/access panel is typically
installed in front of the laser circuit pack shelves The circuit packs themselves,
however, may be FDA/CDRH Class I, IIIb, or IV or IEC Class 1, 1M, 3R, 3B, or 4.
Laser Safety Precautions for Optical Fiber Telecommunication Systems
In its normal operating mode, an optical fiber telecommunication system is totally
enclosed and presents no risk of eye injury. It is a Class I/1 system under the FDA and
IEC classifications.
The fiber optic cables that interconnect various components of an optical fiber
telecommunication system can disconnect or break, and may expose people to laser
emissions. Also, certain measures and maintenance procedures may expose the
technician to emission from the semiconductor laser during installation and servicing.
Unlike more familiar laser devices such as solid-state and gas lasers, the emission
pattern of a semiconductor laser results in a highly divergent beam. In a divergent
beam, the irradiance (power density) decreases rapidly with distance. The greater the
distance, the less energy will enter the eye, and the less potential risk for eye injury.
Inadvertently viewing an un-terminated fiber or damaged fiber with the unaided eye at
distances greater than 5 to 6 inches normally will not cause eye injury, provided the
power in the fiber is less than a few milliwatts at the near IR wavelengths and a few
tens of milliwatts at the far IR wavelengths. However, damage may occur if an optical
instrument such as a microscope, magnifying glass, or eye loupe is used to stare at the
energized fiber end.
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365-312-801R7.2
Issue 3, May 2007
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Alcatel-Lucent - Proprietary
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