Fiber Optic Cable Connectors

Fiber Cable End-Face Inspection: What Is It? Over the past several years, there has been a major increase in the use of fiber optics in networks. Why? Mainly, the demand for more bandwidth, better security, and longer-distance transmission. The need for fiber in the data center and around the campus are also key drivers of its recent popularity. In fiber optic installations, the most commonly used components are the fiber optic patch cable assemblies. It is vital that the connectors on these cables are kept as clean as possible at all times because network performance can suffer when they get dirty. However, checking the cleanliness of fiber cable connectors with the human eye is difficult because they are small and hard to see. So, how do you ensure you re accurately inspecting connectors? This article will explain how to properly inspect fiber cable end faces. It will also detail the most common ways end faces get dirty and why it s important to clean them before connecting them to your network. Why You Need to Clean Fiber End Faces before Installation All fiber patch cable connectors have a ferrule end face where the fiber strand is centered to allow it to mate with another fiber assembly or attach directly to a piece of equipment. If you look at the connector, the ferrule end face is the exposed white ceramic tip of the fiber cable. This tip must be as clean as possible to ensure the best optical results, and you should even check its cleanliness before you install a new fiber cable from the factory into your network infrastructure. Another common way fiber end faces get dirty is when people take the dust cap off the fiber cable and accidentally touch the ferrule end face, contaminating it and introducing light loss that will affect the overall networking performance.The good news is these issues can be solved if you perform a final cleaning before you install your assembly. But still, even after this cleaning, how do you know it s actually clean and ready to use? Fiber Cable End-Face Inspection To ensure cleanliness, you can use a microscope that s specifically made for checking fiber assemblies. These microscopes are normally 100x for multimode and 200x for singlemode inspection. A clean inspection through the microscope typically shows a black dot on a white background.The image below shows two dirty end faces and one clean end face through a fiber microscope. However, even if you get what appears to be a clean end face through a microscope, the question still remains: Is it really clean for the high-speed optical networks of today?To answer this question, inspection microscopes have become more advanced and now use software to scan and take an image of the end face. This process verifies that it is clean and error free for use in optical networks. The software in these microscopes, now more formally known as a tester, follows the accepted testing procedure IEC 61300-3-35 for fiber optic interconnecting devices and passive components.This IEC testing standard takes a visual image of the end face and separates the area into four zones, as follows: Zone A for the core Zone B for the cladding Zone C for the adhesive Zone D for the contact area The zones begin from the end face center core and work their way out, forming concentric circles zones. Each circle zone area may be a little different, depending on the type of fiber end face the microscope is inspecting. Fiber end face testing can be recorded for each assembly, so you can essentially generate a report that validates every assembly was examined prior to installation. This takes out all the human intervention and guarantees the best optical performance.