Diameter of the Ferrule’s Hole Bore Is Larger Than the Outside Diameter of the Fiber

The ferrule hole bore must be slightly larger in diameter than the fiber to allow the fiber to be inserted into the hole. The smaller the ferrule hole diameter, the more precisely the fiber will be centered in the ferrule (thus, lower Insertion Loss can be expected). However, smaller/tighter-tolerance ferrules are more expensive, and can be more difficult to insert the fiber into. Conversely, the larger the ferrule hole, the more opportunity for the fiber to not sit perfectly centered within the ferrule; thus higher Insertion Loss can be expected (but such large-bore holes will be very easy to insert a fiber into).

Knowing the hole specifications for the ferrules you are using is critical to achieve desired IL results. If you are targeting minimum Insertion Loss, you should use the tightest-tolerance ferrule hole diameter available. If you can see a clearly defined “epoxy ring” around the fiber OD when viewing after polishing (usually seen as a thin “crescent-moon” around the fiber), this is the result of the fiber sitting off-center within an oversized ferrule hole. When using a terminated 125um fiber, a 126.0um +/- .5um should be the largest ferrule hole used for most low-loss applications. If your ferrule hole specification is larger than this and you are facing IL performance problems, consider purchasing ferrules with more exacting tolerances.

 

READ THE FULL BLOG ARTICLE HERE: What Causes Poor IL/RL?

 

Additional resources from the FOC team include:

 

Have questions about this FOC Tip?

Contact FOC with questions at: (800) 473-4237 / 508-992-6464 or email: FiberOpticCenter@focenter.com and we will respond ASAP.

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About Fiber Optic Center, Inc.
Fiber Optic Center, Inc., (FOC), is an international leader in distributing fiber optic components, equipment and supplies and has been helping customers make the best cable assemblies in the world for over two decades. Several areas of specialization and expertise, in which they are the industry leader, make them the preferred choice for many of the world’s fiber professionals. In these key technology areas, FOC is "at least as technical as the manufacturer" about the products they sell. Striving to "make the business part easy," they offer outstanding and personal customer service, low or no minimum purchase order values, and from-stock delivery on industry-leading products and technology. FOC is the industry connection to the most innovative optical products, technologies and technical experts who integrate their manufacturing knowledge and vast experience into customers' worldwide operations. @FiberOpticCntr

For further information contact:
Fiber Optic Center, Inc., 23 Centre Street, New Bedford, MA 02740-6322
Toll Free in US: 800-IS-FIBER or 800-473-4237 . Direct 508-992-6464. Email: sales@focenter.com or fiberopticcenter@focenter.com

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Kathleen Skelton, Director of Strategic Marketing, C: 617-803-3014 . E: kskelton@focenter.com