This document discusses Free Space Optic (FSO) technology, which uses lasers and photodetectors to transmit data, voice, or video at speeds up to 2.5 Gbps in an optical connection without the need for fiber. FSO consists of an optical transceiver with a laser transmitter and photodetector receiver to provide bidirectional communication using invisible infrared laser light. While FSO has advantages like huge bandwidth and low interference, it also has disadvantages such as needing line of sight and being susceptible to signal scattering. The cost of installing FSO units on a campus is estimated to be $4,600-$26,840 per connection depending on indoor or outdoor installation requirements.

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FSO Free Space Optic
Prepared by: Abel Ngetich
Course: NETW 589
Instructor: Professor Mohamad
Haidar

2. Introduction
 FSO is a line of sight technology which uses
LASERs and Photo detecters to provide optical
connections between two points without the fiber.
 Transmission of visible and infrared IR beams
through the atmosphere
 FSO can transmit data, voice or video at speeds
capable of reaching 2.5 Gbps
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3. Continuation
 FSO consists of an optical transceiver with a Laser
(transmitter) and a photo detector ( receiver) to
provider full duplex (bi-directional ) capability
 FSO systems use invisible infrared laser light
wavelengths in the 750nM to 1550 nM
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4. Campus Layout
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5. Advantages of FSO
 Unregulated spectrum
 Huge bandwidth
 No strict laws
 Optoelectronic technology
 Less interference
 Immunity to electromagnetic interference
 Reusability
 Low Power consumption
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6. Disadvantages of FSO
 High launch represent eye hazard
 Low power source requires light sensitive receivers
 Alignment leads to more operation constraints
 Signal scattering results in multipath impairment
 Blockage lead to design challenges
 Light interference negatively affects system
performance
 Scintillation
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7. 7
Cost of installation
Typical Installation Tasks for Each FSO Unit Indoor Rooftop
AC Branch Circuit
One 20amp dedicated circuit run a maximum of 50 ft
450
10-Story Communications Riser (rooftop only) Flexible 1 1/4”
conduit with fiber, CAT5 & 2 communications cables
$ 3,200
10-Story AC or DC Riser (rooftop only) 1” metal conduit $ 4,520
Behind Window Mounted FSO Unit (indoor system) Includes
tripod floor mount with Unit mounted & terminated
$ 1,250
Roof Top Mounted FSO Unit Includes tripod flat roof mount
with Unit mounted & terminated.
$ 2,800
Roof Riser Penetrations $ 1,500
Roof Riser Repairs (estimated) $ 1,400
Total per unit $ 2,300 $13,420
Total cost for the two units $ 4,600 $ 26,840

8. Are the cost opex or capex?
• Opex is operational expenses such as wages,
maintenance services, repairs, utilities and
rent.
• Capex refers to capital expenditures such as
purchasing equipment and inventory
 The cost of installation is more than the cost of
maintenance of FSO. Therefore it is
categorized as Capex cost
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9. Permit
The following are some of the permits required
by the jurisdiction within which FSO is to be
installed.
 Municipal or county council permit
 Developmental permit
 Environmental permit
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10. Continuation…
• Installation and operation of FSO
requires no FCC licensing or RF
spectrum licensing .
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11. Data Security
• In FSO an infrared beam slightly above the
visible spectrum is used hence it is invisible to
normal human eyes.
• Any attempt to interrupt the beam is possible
only near the receiver terminus as it passes in
a line of sight which is invisible
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12. Conclusion
FSO is recommendable to such
environment such as university campus or
connecting buildings in a city. It is less
expensive and requires no spectrum
licensing. It is more secure because it
requires no security software.
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13. Reference
Infrared Data Association http://www.irda.org
http://www.atekcommunications.com/nationalfsoi
nstallations.htm
http://www.cablinginstall.com/articles/print/volum
e-18/issue-3/features/free-space-optics.html
http://www.freespaceoptic.org
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