Many customers have asked several times: Why do fiber optic connectors fail? I've been in the fiber optic industry since the 1980s, and despite the amazing advances in technology, this problem still plagues fiber optic connector manufacturers.
Did you guys know there are 4 diagnostics that can help troubleshoot the cause of a fiber optic connector failure? As you can guess from the title of this article, my favorite diagnostic method is the cross-section fiber optic connector. This technology allows us to actually look inside the fiber optic connector to see defects and pinpoint the cause of the failure.
Let's see an example:
Here's a photo I took while cutting a fiber optic connector for a client. The fiber optic connector is first vacuum impregnated with metallographic grade epoxy resin. It is then cut into various locations and terminated at approximately the longitudinal midpoint of the fiber in the ceramic ferrule.
Cross sections allow us to zero in on specific areas of the fiber optic connector assembly to identify potential defects. When analyzing this cross-section fiber optic connector, I found several local fiber breaks in critical areas as well as a complete fiber break.
fiber optic connector failure
In these magnified images of this fiber optic connector, note the partial breakage of the fiber at critical locations.
The optical fiber connector
Here are other enlarged images of the same fiber optic connector. Note the localized breakage of the fiber within the confines of the fiber-bonding epoxy.
In the same fiber optic connector, the gap between the epoxy-bonded fiber and the inner fiber-optic connector surface indicates that the epoxy-bonded fiber exhibits significant shrinkage. In the image above, notice the apparent shrinkage of the fiber-bond epoxy at the red arrow.
Cross-sectioning is an effective diagnostic tool and a practical solution to identifying process problems, which can be resolved.
As you can see from the photo above, the cross section provides the unique ability to identify and isolate issues related to fiber terminations that would otherwise be invisible. A cross-sectional service at the center of the fiber can reveal breaks, nicks, microbends, shrinkage, and microcracks in the fiber. Insufficient/too much epoxy or air bubbles in the epoxy; and problems with stripping, curling, etc.
When a fiber optic connector fails, the cross section can help determine the cause and identify process problems. Fiber Center customers rely on this diagnostic service to visually analyze their fiber optic connectors, identify defects, diagnose potential causes and implement process improvements.
This enables you to perform regular audits and quick failure analysis when you implement internal transversal capabilities.
I encourage you to consider implementing the cross-section functionality internally in your own test environment. We can help you set up your equipment, then train you to perform tests and interpret results. When things go wrong, you can call us - we're a resource you can rely on.
When this functionality is implemented in-house, routine cross-sectioning can be performed to monitor the quality of fiber optic cable assemblies. Plus, you can perform a quick failure analysis within a few hours for immediate problem resolution.
