News
Issue #2002 - 40 (October 2002)
(Updated Oct. 22, 2002)

TECHNOLOGY

Free Space Optics (FSO) - a Wireless Fiber Alternative for Broadband Communications. 

Fiber is indisputably the most effective infrastructure for Gigabit Ethernet transmissions, in terms of speed, security and reliability. However, where fiber infrastructure does not exist, it is costly and time-consuming to install. 

Quick Deployment of Massive Bandwidth:  Also dubbed wireless optical networking or wireless fiber, free space optics (FSO) is used by enterprises to transmit data via laser at speeds of up to 2.5 Gbps in point-to-point or, in the near future, point-to-multipoint topologies. In addition to its high bandwidth capacity, advantages of this broadband technology include fast deployment (within a matter of days) and low cost, with very low capital expenses. There is no need to apply for and wait to receive licenses, as none are required for FSO frequencies. The fiber link can connect the node to any type of backbone, such as ATM and IP.

RAD is one of the vendors supplying FSO-capable  equipment. RAD's ACE family of ATM network termination devices features a wide variety of user interfaces, for connecting to any type of user equipment to the optical network. For Ethernet networks, RAD's IPmux family of TDM over IP (TDMoIP) gateways extends E1/T1 circuits over IP-based networks, enabling connection of the customer's legacy PBX over the Ethernet network, maintaining all existing customer equipment and telephony features.

Common Applications: FSO can be used as the main infrastructure or as a backup path in case the fiber network is cut or damaged in some way. An important application for FSO is disaster recovery, as evidenced in the aftermath of the September 11 tragedy. When the fiber infrastructure was knocked out, many businesses employed FSO to connect their offices to the networks in buildings in their line-of-sight. Rockefeller Group Telecommunications Services, for example, used FSO connected to RAD's IPmux TDM over IP gateway, to provide fast telephone connectivity to relocated users over Ethernet, connecting them to a working PBX in another building. 

FSO is also used to complement existing networks to increase their range and capacity. There is reasonable interoperability between major FSO equipment vendors, including RAD, Lightpointe, Terabeam, Optical Access, fSONA and Canobeam.

Enterprises considering FSO should bear in mind that there are several limitations to this technology. Laser transmissions require a line-of-site between nodes. (Strategically placed mirrors can be used if no line-of-site exists.) Although theoretically FSO can operate at distances of up to 2 km/1.2 miles, in practice it is effective for distances of less than 1 km/.6 miles. For these reasons, FSO is used primarily in dense urban areas to provide point-to-point campus connectivity or broadband Last Mile service. The most serious impediment to widespread use of FSO is caused by weather conditions, especially fog. The small moisture particles scatter the light beam, thereby interrupting the optical transmission. 

For more information: www.freespaceoptic.com and www.rad.com

MobileInfo Comments and Advisory: FSO will become more common place technology especially with multipoint capability. While fiber will rule for capacity, reliability and security, FSO is an alternative that may be cheaper and a good alternative in metropolitan area network applications. 

Note: This news release may contain forward-looking statements. Readers should take appropriate caution in developing plans utilizing these products, services and technology architectures.  All trademarks used in this summary are the property of their respective owners.