OPTOKON EDFA User Manual page 8

EDFA optical amplifier – user manual
Class 1M
A Class 1M laser is safe for all conditions of use except when passed through magnifying
optics such as microscopes and telescopes. Class 1M lasers produce large-diameter beams,
or beams that are divergent. The MPE for a Class 1M laser cannot normally be exceeded
unless focusing or imaging optics are used to narrow the beam. If the beam is refocused,
the hazard of Class 1M lasers may be increased and the product class may be changed. A
laser can be classified as Class 1M if the total output power is below class 3B but the
power that can pass through the pupil of the eye is within Class 1.
Class 2
A Class 2 laser is safe because the blink reflex will limit the exposure to no more than 0.25
seconds. It only applies to visible-light lasers (400–700 nm). Class-2 lasers are limited to 1
mW continuous wave, or more if the emission time is less than 0.25 seconds or if the light
is not spatially coherent. Intentional suppression of the blink reflex could lead to eye injury.
Many laser pointers are class 2.
Class 2M
A Class 2M laser is safe because of the blink reflex if not viewed through optical
instruments. As with class 1M, this applies to laser beams with a large diameter or large
divergence, for which the amount of light passing through the pupil cannot exceed the
limits for class 2.
Class 3R
A Class 3R laser is considered safe if handled carefully, with restricted beam viewing. With
a class 3R laser, the MPE can be exceeded, but with a low risk of injury. Visible continuous
lasers in Class 3R are limited to 5 mW. For other wavelengths and for pulsed lasers, other
limits apply.
Class 3B
A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as
from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength
range from 315 nm to far infrared are limited to 0.5 W. For pulsed lasers between 400 and
700 nm, the limit is 30 mJ. Other limits apply to other wavelengths and to ultrashort
pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B
laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety
interlock.
Class 4
Class 4 lasers include all lasers with beam power greater than class 3B. In addition to
posing significant eye hazards, with potentially devastating and permanent eye damage as
a result of direct beam viewing, diffuse reflections are also harmful to the eyes within the
distance called the Nominal Hazard Zone. Class 4 lasers are also able to cut or burn skin.
In addition, these lasers may ignite combustible materials, and thus represent a fire risk, in
some cases. Class 4 lasers must be equipped with a key switch and a safety interlock.
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