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Ribbon vs. Loose Tube
Fiber Cabling
Ribbon vs. Loose Tube
Fiber Cabling
Making the Right Fiber Cable Choice can Improve Overall
Performance of Distribution Cables in the PON
In the distribution portion of the passive optical network (PON) for fiber-to-
the-premise (FTTP) architectures, the choice of fiber cabling – ribbon vs. loose
tube – can directly impact ease of installation and future performance. As is
usually the case in these networks, specific architectural characteristics and
particular applications may dictate the deployment of one type of cable over
the other. However, ADC’s experience in developing and manufacturing FTTP
network equipment has concluded that in most cases, ribbon cable provides a
considerable performance advantage over loose tube in the distribution portion
of the PON network.
Fiber Density is Key
The most obvious asset for ribbon cable is its higher fiber density. This is
particularly important for upstream applications requiring high fiber-count cables.
Material costs decrease since less plastic is involved and fewer strength members
are required. Additionally, it takes significantly less termination time (and cost)
with ribbon cable because of its mass fusion splicing capability as compared
to one-by-one fiber splicing. Even with techniques available for “ribbonizing”
loose tube fibers – basically stacking the fibers and using a spray adhesive to
simulate ribbon cable – for mass fusion splicing, using ribbon cable to begin with
eliminates the need for this extra step.
Ribbon is, therefore, a better choice for termination in areas of the network that
require a high volume of fibers. As the network branches farther out towards
the premise, the need for high fiber-count cables decreases. Once the density
becomes less than 144 fibers, loose tube cables have certain advantages. For
example, loose tube cables offer the ability to peel off single tubes to access

even the ribbon cable in the fiber distribution hub must
perform as intended over the temperature ranges.
It’s been ADC’s experience that for connectorized
distribution cabling inside the FDH, putting connectors
on ribbon cable works far better than any loose tube
cable because of the thermal expansion and contraction
of the sub-units.
In temperatures starting at about 32 degrees F, the
tubing in loose tube cables contracts substantially while
the fibers remain in place. This phenomenon induces
cable loss caused by attenuation in connectorized loose
tube distribution cables of as high as 10 dB. There are
only two ways to accommodate the expansion and
contraction of the sub-units. One way is to slit the
sub-unit material to make it “free-floating” over the
fibers. This isn’t recommended since it leaves multiple
fibers unprotected. The second alternative is simpler
– choose a vendor whose products exhibit less of this
phenomenon or who has achieved a time-tested way
to mitigate it. Most manufacturers of loose tube cable
recommend maximum tube lengths of 8 feet outside of
the OSP jacketing. Even at these lengths, ADC has often
observed considerable shrinkage of buffer tubes, leading
to temperature-induced losses at high wavelengths if the
cable assembly is not properly designed.
Ribbon cables simply do not have this problem. It’s
avoided by having all the cables in a central tube that
allows ample room for the fibers to move around as
sub-unit materials expand and contract. Although it may
not be considered a significant advantage, ribbon cables

cost. However, on the distribution side of the FDH, a
connectorized ribbon cable simply performs far better
than a connectorized loose tube cable. When giving
careful consideration to issues such as size, density, and
restoration of cables, it appears ribbon cables are the
best choice.
Ribbon vs. Loose Tube Fiber Cabling
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Specifications published here are current as of the date of publication of this document. Because we are continuously
improving our products, ADC reserves the right to change specifications without prior notice. At any time, you may
verify product specifications by contacting our headquarters office in Minneapolis. ADC Telecommunications, Inc.
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101098AE 11/06 Revision © 2005, 2006 ADC Telecommunications, Inc. All Rights Reserved
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