363-206-305
Page 6 of 12 Issue 3, June 2000
DDM-2000 F
IBER
R
EACH
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IDEBAND
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HELF
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 — Class I, II, IIa, IIIa, IIIb, or IV. Lasers are classified
according to the accessibly emission limits and their potential for causing injury. Lightwave
systems are generally classified as Class I, because, under normal operating conditions, all
energized laser transmitting circuit packs are terminated on optical fibers which enclose the
laser energy with fiber sheath, forming a protective housing. Also, covers are in place over
the circuit pack shelves.
Lightwave Safety Precautions
In its normal operating mode, a lightwave system is totally enclosed and presents no risk of
eye injury. It is a Class I system under the FDA/CDRH scheme.
The lightguide cables that interconnect various components of a lightwave system can
disconnect or break, and may expose people to lightwave emission. 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 intensity) 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 unterminated 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 mW at the shorter wavelengths and higher at the longer
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.
!
CAUTION:
Use of controls or adjustments or performance of procedures other than those
specified herein may result in hazardous laser radiation exposure.
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