Browse Prior Art Database

Strain Relief for Optical Fibers at Entrance Or Exit From a Duct

IP.com Disclosure Number: IPCOM000100480D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Corbett, SA: AUTHOR [+2]

Abstract

The typical method of packaging optical fibers for installation in buildings is by incorporating them into a traditional cable structure, similar to that used for copper wire. However, because of the light weight and flexibility of fiber, it can be blown into place through a tube or duct which has previously been installed between the two points to be interconnected. Some of the advantages of this technology are the flexibility it provides in choosing optical parameters of the fiber after the duct has been installed and the ability to change fiber types without pulling a new cable into place.

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Strain Relief for Optical Fibers at Entrance Or Exit From a Duct

       The typical method of packaging optical fibers for
installation in buildings is by incorporating them into a traditional
cable structure, similar to that used for copper wire.  However,
because of the light weight and flexibility of fiber, it can be blown
into place through a tube or duct which has previously been installed
between the two points to be interconnected.  Some of the advantages
of this technology are the flexibility it provides in choosing
optical parameters of the fiber after the duct has been installed and
the ability to change fiber types without pulling a new cable into
place.

      New problems are also presented, and other problems are
exacerbated by the blown fiber technique.  One of these is the large
difference in stiffness (section modulus) between the duct and the
individual fibers as they enter and exit the duct.  It is also
desirable to provide a protective covering, possibly including
strength members, to shield the fiber from external stresses between
the point where it exits the duct and where it is terminated at a
connector, splice or other interconnecting device.

      As is shown in the figure, a strain relief assembly is used to
protect the fiber during this transition.  A molding can be made
which snaps on to the duct, or is otherwise fastened thereto.  The
molding has grooves to guide the fibers from the end of the duct and
into breakout tubes at...