Alcatel-Lucent 1643 AMS Applications And Planning Manual page 18

About this information product
Optical Safety Declaration (if laser modules used)
Alcatel-Lucent declares that this product is compliant with all essential safety
requirements as stated in IEC 60825-Part 1 and 2 "Safety of Laser Products" and
"Safety of Optical Fiber Telecommunication Systems". Furthermore Alcatel-Lucent
declares that the warning statements on labels on this equipment are in accordance
with the specified laser radiation class.
Optical Fiber Communications
This equipment contains an Optical Fiber Communications semiconductor laser/LED
transmitter. The following Laser Safety Guidelines are provided for this product.
General Laser Information
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 (nm) and 1600 nm. The emitted
light is above the red end of the visible spectrum, which is normally not visible to the
human eye. Although radiant en 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.
Lasers and Eye Damage
The optical energy emitted by laser and high-radiance LEDs in the 400-1400 nm range
may cause eye damage if absorbed by the retina. When a beam of light enters the eye,
the eye magnifies and focuses the energy on the retina magnifying the irradiance. The
irradiance of the energy that reaches the retina is approximately 105, or 100,000 times
more than at the cornea and, if sufficiently intense, may cause a retinal burn.
The damage mechanism at the wavelengths used in an optical fiber telecommunications
is thermal in origin, i.e., damage caused by heating. Therefore, a specific amount of
energy is required for a definite time to heat an area of retinal tissue. Damage to the
retina occurs only when one looks at the light long enough that the product of the
retinal irradiance and the viewing time exceeds the damage threshold. Optical energies
...................................................................................................................................................................................................................................
xviii Alcatel-Lucent - Proprietary
See notice on first page
365-312-801R7.2
Issue 3, May 2007
,