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".

Through 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 the retina.

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 2.

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.