2 System aspects

2.1 Apparatuses laser safety

Any laser can present danger to man, at ocular level and at cutaneous level; the human eye being very sensitive to infrared radiation. The most important factors to take into account to evaluate the risks are: the signal wavelength, power and beam form. Eye safety is governed by International Electrotechnical Commission (IEC) standards. Those in force in France are: NF EN 60825-1 and NF EN 60825-2. The lasers are divided in various classes according to the known risks which they represent, allowable exposure limit (AEL), allowable maximal exposition (AME) and nominal distances of ocular risk (NDOR).

2.2 Manufacturers and products

A review manufacturers was carried out, based on various sources of information (conferences, reviews, magazines, research engines, web sites etc) in order to obtain the most complete possible panorama of products and their capabilities.

The principal parameters considered are transmitted data type, range, data rate and the type of suggested application or other parameters such as the wavelength, type and number of optical transmitters (laser and possibly LED), emitted power, control, deployment facilities, maintenance, cost etc. Table 18.1 gives an overall picture of most of the products listed starting with information obtained by manufacturers or by consulting their web site. Figures 18.1 and 18.2 (at the end of the chapter) give the data rate suggested (Mbits/s) and range in function of the wavelength for various equipment.

Figure 18.1: Data rate (in Mbps) in function of the wavelength for various equipments

Figure 18.2: Range in function of wavelength for various equipments

Table 18.1: Manufacturers of free-space optical products
Manufacturers	City	Country	Internet site
ACTIPOLE	Le Bouscat	France	http://www.laser-com.com
AirFiber Inc	San Diego (CA)	USA	http://www.airfiber.com
Airlinx		Canada	http://www.laseroptronics.com
Astroterra	San Diego (CA)	USA	http://www.astroterra.com
CABLEFREE		UK	http://www.cablefree.co.uk
GUN	Amsterdam	Holland	http://www.canon-europa.com
CBL	Munster	Germany	http://www.cbl.de
Eagle Optoelectronics	Boulder	USA
Firlan	Ottawa	Canada	http://www.firlan.com
FSONA	Ricmond B.C.	Canada	http://www.fsona.com
GoC	Dreieich	Germany	http://www.goc.de
Infrared Com. Syst.	Edmonds	USA	http://www.laserinfraredwireless.com
JOLT	Jerusalem	Israel	http://www.jolt.co.il
LASERBIT	Budapest	Hungary	http://www.laserbitcommunications.com
Laser Com. Syst.		USA	http://www.powertechnology.com
Laser Syst Diode.	Hawthone (Ca)	USA	http://www.ldsc.net
LIGHTPOINTE	Boulder	USA	http://www.lightpointecom.com
LSA	Exton	USA	http://www.lsainc.com
Lucent Technologies	Plessis Robinson	France	http://www.lucent.com
MDS	Taluyers	France	http://www.mds.fr
OPTEL	Hamburg	Germany	http://www.optel.de
OPTICAL ACCESS	GIF/Yvette	France	http://www.opticalaccess.com
OrAccess	New Indus.Zone	Israel	http://www.oraccess.com
PAV Dated Systems	Cumbria	England	http://www.pavdata.com
Plaintree Systems	Nepean	Canada	http://www.plaintree.com
SILCOM	Ontario	Canada	http://www.silcomtech.com
TeraBeam Networks	Seattle	USA	http://www.terabeam.com

2.3 Uses

In this paragraph the various uses suggested by the manufacturers are mentioned. In an artificial way, they were classified in three types of approaches: geographical, application and technical.

2.3.1 Geographical approach

Initially, an approach related to geographical specificities, is presented below, including:

Isolated sites (mountainous sites, places of interest) or risks (lightning, IEM).
Charged electromagnetic environments (airports, factories, etc).
Classified sites, private domains,
Not easily passable obstacles (motorways, rivers, etc),
Dense urban zones.

2.3.2 Applications approach

A second approach relates to the applications aspect of a free-space optical communication link.

temporary link,
- event action link (sport, concert, etc),
- intervention link (work, modification or network repair, etc),
- help link ( accident , fast commercial action, etc),
"last mile" connection,
inter-site connection, independent, rented or private networks,
closing an optical loop,
inter- cell GSM or UMTS link (micro or picocell), etc.

2.3.3 Interface approach

This approach relates to the various types of interfaces available with a laser link. Products with interfaces of any types in the various potential fields of application are proposed by the majority of manufacturers:

LAN Networks (Ethernet, Fast Ethernet, GigaEthernet, FFFDI, Token Ring, etc),
Telecom (E1, E3,T1 T3, ATM, SONET, SDH, PDH, etc),
Video (SDI, SMPTE, etc),
Mixed LAN-Telecom (Ethernet 10BaseT and 2xE1).