Fiber Optic Association
- Tech Topics
Optical Fiber (POF)
Plastic optical fiber (POF)
has always been
"lurking in the background" in fiber optics; a specialty
fiber useful for illumination and low speed short data links.
There is now a greatly increased interest in POF, as R&D has
given it higher performance to go along with its ease of installation
and low cost.
POF is large core step-index
a typical diameter of 1 mm. This large size makes it easy to couple
lots of light from sources and connectors do not need to be high
precision. As a result, typical connector costs are 10-20% as
much as for glass fibers and termination may be as easy as cutting
with a razor blade! Being plastic, its also rugged and easy to
install without fear of damage.
From an optical standpoint,
POF is much lower in performance than glass fiber. It has a loss
of 0.15-0.2 dB per meter at 650 nm and its bandwidth is limited
by its large NA and step-index profile. However, it is adequate
for running short links, such as inside of instruments or within
a room for desktop connections up to 50 meters. And of course
in automobiles, where it has gained a foothold with the new MOST and Flexray
But recent developments in POF
have led to low NA POF that offers higher bandwidth and graded-index
POF (GI-POF) that combines the higher bandwidth of graded-index
fiber with the low cost of POF. Current designs of GI-POF offer
up to 2 Ghz bandwidth at distances of 100 meters, but manufacturing
problems have hampered its adoption. Recent developments in a
new laser (VCSEL of vertical cavity surface emitting laser) promise
extremely low cost, high power, high speed transmitters.
POF offers promise for desktop
It can be installed in minutes with minimal tools and training.
Bandwidth exceeds anyones estimates for the next decade. Prices
are competitive with copper. Standards groups are now looking
at options for POF. POF could prove the next viable desktop connection.
POFTO - The Plastic Optical Fiber Trade Organization
- is a source of information on POF.
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