True Eye-Safe technology
The International Standards Organization (ISO) rates eye-safety on a scale
between one and four, where Class 1, the safest rating, is defined as "Safe
under reasonably foreseeable conditions. No limitations on radiation wavelength"
and Class 4 is "Capable of producing hazardous diffuse reflections. Not
permitted for laser communications".
the use of a unique combination of infra-red wavelength and receiver optics,
fSONA's product achieves a Class 1 rating for eye safety. British Telecom
Labs developed its laser technology with Class 1 laser emission as the key
objective. Most other competitors use infra-red frequencies in the 850-980
nm range, which combined with the optics and power emission requirements
of the laser, can only achieve Class 3B standards - always hazardous.
Currently, various regulatory agencies in the United States and Europe are
contemplating legislating against the use of non-eye-safe laser based products
in populated urban areas. Should this occur, fSONA's SONAbeam product
line would be one of only two laser technologies approved for use in the
metropolitan marketplace, and the only cost-effective solution for CLECs.
The key to SONAbeam's breakthrough laser technology is its operational
wavelength of 1550 nm, which provides a broad spectrum of safety and performance
advantages. fSONA products exclusively use the 1550 nm optical wavelength
region for eye safety.
SONAbeam is a Safe Alternative
With the proliferation of optical wireless communication products directing
laser beams into potentially populated areas, the issue of laser eye safety
becomes of increasing significance for public safety and system operator
liability. Because biophysical characteristics of the eye are quite different
for the two predominant optical-wireless wavelength bands, eye-safety considerations
play a key role in the overall system wavelength trades.
The optical wireless hardware currently on the market can be classified
into two broad categories - systems that operate near 800 nm wavelength
and those that operate near 1550 nm. Laser beams at 800 nm wavelength are
near-infrared and therefore invisible, yet like visible wavelengths the
light passes through the cornea and lens and is focused onto a tiny spot
on the retina. The collimated light beam entering the eye in this retinal-hazard
wavelength region is concentrated by a factor of 100,000 times when it strikes
At 800 nm the retina could be permanently damaged by some commercially available
optical-wireless products before the victim is aware that hazardous illumination
has occurred. It is possible to design eye-safe laser transmitters at both
the 800 nm and 1550 nm wavelengths, but due to the aforementioned biophysics
the allowable safe laser power is about fifty times higher at 1550 nm. This
factor of fifty is important to the communication system designer, because
the additional laser power allows the system to propagate over longer distances
and/or through heavier attenuation, and to support higher data rates.
Laser eye safety is classified by the International Electrotechnical Commission
(IEC), which is the international standards body for all fields of electrotechnology.
While the IEC is an advisory agency, its guidelines are adopted by the regulatory
agencies in most of the world's countries. A laser transmitter which is
safe when viewed by the eye is designated IEC Class 1M. A transmitter which
is also safe when viewed with a 25 mm binocular is designated IEC Class
1. Laser Safety classifications are summarized in IEC Document 60825-1 Amendment
In the United States, laser eye safety is regulated by the Center for Devices
and Radiologic Health (CDRH), a division of the Food and Drug Administration.
Currently, the CDRH is operating in an interim period while in the process
of adopting the safety classifications of IEC 60825-1am.2. Unfortunately,
during this interim period some manufacturers are forced to label their
products as Class 3B, even though the products are eyesafe according to
IEC Class 1M. It may take until 2003 for the CDRH to complete their standards
revision, and CDRH is expected to issue guidelines to manufacturers in early
2001 about how to minimize the impact to products during this interim period.