The Fiber Optic Association - Tech Topics
Plastic 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 multimode fiber with 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 and no or minimal polishing.
Being plastic, its also rugged and easy to install without fear of damage.
From an optical standpoint, conventional POF is much lower in performance
than glass fiber - higher attenuation and lower bandwidth. 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 networks.
But recent developments in POF technology 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.
POFTO - The Plastic Optical Fiber
Trade Organization - is a source of information on POF.
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