white paper
OmniReach
™
FTTP Solutions
The Situation
It is common in applications where access terminals are used to terminate only a portion of the
fibers brought into the enclosure–allowing the remainder of the fibers to pass through. When
loose tube cable is used, the sub-units that are not terminated are "expressed" through, and
the sub-unit material is not opened at any point. To provide customers with adequate sub-unit
length for splicing under all conditions, ADC specifies a mid-span access length of 150" to
170". Testing of the enclosure with expressed sub-units of this length alerted ADC to potential
low temperature issues.
While there are no written standards governing this application, ADC has concluded that in
some - but not all - cases, loose tube OSP cable, dielectric or armored, can experience excessive
attenuation loss at low temperatures (0˚C to -40˚C). Subsequent research also reveals that the
issue becomes more severe for cables exposed to initially high temperatures (greater than 50˚C)
prior to their exposure to low temperatures. Attenuation loss can be as high as 10 to 20 dB in
extreme cases.
After identifying the problem, ADC proactively began researching the probable cause and
discovered information from a 1998 Bellcore white paper that outlined similar problems with
certain fibers in varying temperature environments. The paper, entitled "Time- and Temperature-
Dependent Material Behavior and Its Impact on Low-Temperature Performance of Fiber Optic
Cables," by Osman S. Gebizlioglu, seemed to address the very issue ADC was observing in
several of its own case studies.
According to the paper, "a series of service-affecting field failures in cold weather (-40 degrees
C to 0 degrees C) initially and in more moderate conditions (up to 15 degrees C) recently have
raised concerns about the temperature-dependent transmission performance of loose tube fiber
optic cables." The effect was transmission loss "resulting from fiber microbending due to
random fiber contacts with the buffer tube walls caused by the axial shrinkage of the buffer
tubes relative to the cable central member."
With Bellcore's previous research confirming ADC's own data, engineers set out to pinpoint and

proactively addressing and solving potential problems such as these, ADC continues to reaffirm its
role as the industry leader in customer satisfaction.
References
O.S. Gebizlioglu, "Time- and Temperature-Dependent Material Behavior and Its Impact on Low-
Temperature Performance of Fiber Optic Cables." (1998)
ADC Telecommunications, Inc., P.O. Box 1101, Minneapolis, Minnesota USA 55440-1101
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. views its patent portfolio as an important corporate asset and vigorously enforces its patents.
Products or features contained herein may be covered by one or more U.S. or foreign patents. An Equal Opportunity Employer
1304851 9/04 Original © 2004 ADC Telecommunications, Inc. All Rights Reserved
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