[comm]Free Space Optics Lunch Talk

[Tracy Effland]

Gene and I attended the January meeting of the Virginia
Telecommunications Association (VTA) on January 16th, 2002. The topic
was "Introduction to Free Space Optics: Ultra-High Bandwidth Wireless
Solution" and the speaker was Isaac I. Kim, Director of Research at
Optical Access, Inc.

Optical Access Networks offer solutions for linking a network between
buildings or sites over a wide variety of interfaces. The systems are
great solutions to many last mile problems and the need for emergency
networks. Below, are  lists of advantages, disadvantages and
specifications of the products.

Advantages:
- Rapid Deployment of a pair of Scopes.
- No reoccurring lease costs.
- Prices range from $2,000 - $48,000 for a pair of Scopes, depending on
speed & distance.
- Camera inside units to align Scopes
- A mux can be used to send different protocols over link.
- Uses a narrow transmission beam that provides security.
- Claim 99.999% availability in all types of weather and the
availability can be predicted.
- Radio backup link is available as an option.
- MTBF on lasers is 8-10 years and they operate between 45-55% capacity
to extend life.
- No licenses required.


Disadvantages:
- Distance range of 200 meters to 4+ Kilometers.
- Mounting is simple but Scopes only tolerate limited sway.
- Line of sight limitation.
- Sand storms can bring the link down.

Specifications:
- Power requirements - 300 Watts with heater and 15-20 Watts without
heater (used to keep glass clear).
- Terascopes are offered with either indoor or tower mounts.

Scopes are at http://www.opticalaccess.com/products-ts.shtml

Whitepapers are at http://www.opticalaccess.com/news-white-papers.shtml

Notes:
RF models operate at a lower bandwidth and the TS3000 model accommodates
both low and high bandwidths.

Conclusion:
Their purchase price and ease of installation make these units very
attractive alternatives to fixed cable or radio installations assuming
there is line of sight and the distance is within their capability.  The
technology used by Terascopes should be kept in mind as possible
solutions to providing connections between buildings or test platforms
at the VLA and Green Bank sites.  If line of sight permits these units
could be used to replace leased lines at the KP and MK VLBA sites.