What Affects Fiber Patch Cord Quality?

Since fiber optic cables have been brought to the telecommunication market, fiber patch cord, made up of a fiber optic cable which is terminated with connector on both ends, has stepped all over the world and experienced significant use in communication networks. Fiber patch cord, or called fiber optic jumper, boasts of various advantages over copper wires, featuring lighter weight, greater flexibility, and faster transmission speed over longer distance. As the deployment of fiber optic jumper increases in both public and private networks, jumper performance is critical to system integrity and reliability. However, many factors can affect patch cord quality and performance. If fiber optic jumper provides the insertion loss and reflectance performance required, does this mean a reliable system? Maybe not. What about the fiber position? Would this affect the performance? Maybe yes. Feel confused now? Don’t worry. This text gives some factors that have impacts on fiber patch cord reliability and quality.

Insertion Loss & Reflectance

It’s known that insertion loss (IL) and reflectance constitute the basic performance parameters of a connectorized cable assembly. IL is the loss of signal power resulting from the insertion of a device in a cable, and is usually measured in decibels (dB). This IL can be tested by using a light source and power meter (LSPM image shown below), commonly referred to as an optical loss test set (OLTS). Certainly, IL can also be expressed by an optical time domain reflectometer (OTDR) which is more often used to measure reflectance for discrete components or optical return loss (ORL) for tip-to-tip systems. In analog and digital video, when ORL is less than 27dB, then instability in a laser source is caused, causing poor-quality image.

Radius of Curvature

Just as the first paragraph mentioned, just IL and reflectometer can’t exactly ensure the quality required in patch cords. Here go to other parameters.

Radius of curvature (ROC) is the radius of the ferrule endface which is measured from the axis of the ferrule. When the radius is between 7mm and 25mm, then the correct compressed force is ensured between two mated connectors. The internal spring in a connector exerts a predetermined force to compress and deform the ceramic ferrules and glass fibers, resulting in a contact footprint between 150µm and 200µm in diameter. If the ROC is less than 7mm, this force is concentrated into a smaller contact footprint and the risk of shattering the glass fiber increases. If the ROC is more than 25mm, the contact footprint increases and physical contact may be compromised, resulting in increased reflectance and insertion loss.

Fiber Position & Cleanliness

Fiber position refers to the protrusion or undercut of the fiber endface which is related to the ceramic ferrule at the axis of the fiber. While maintaining the physical contact of two mated fibers, the position plays a really important part. Too much protrusion may cause the fiber to shatter, and too much undercut may lead to loss of physical contact, leading to increased reflectance and insertion loss.

Cleanliness is also critical in attaining needed IL and reflectance performance. Here include endface debris and defects. Inspection with 200x or 400x magnification should be performed against an industry standard such as IEC 61300-3-35. Large defects such as scratches and pits can collect and transfer dirt to an opposing connector, sometimes creating additional defects. Each time the connector is mated or re-mated, the opposing connector should be properly cleaned.

The Use of Bend-insensitive Fiber

Another parameter is the use of bend-insensitive fiber in fiber optic jumpers. This kind of fiber is designed in both single-mode and multi-mode versions. Its use greatly reduces issues with routing bends or pinching that, in some cases, are difficult to locate, even with a visual fault locator. Besides, using this bend-insensitive fiber can avoid the frustration of troubleshooting a system for hours, helping to eliminate installation errors, and ensuring that future activity around a rack or in a cabinet does not bring about downtime or hours of troubleshooting.

Conclusion

With many providers from whom to choose fiber patch cords, to get a better understanding of those factors that ensure quality and performance is essential in selecting a jumper of high quality. But there are also situations that some users or contractors pay much for patch cord, but get low quality products which not tightly controlled during manufacturing. Fiberstore, an outstanding fiber patch cord manufacturer, helps you to clear off such problems. Its fiber optic patch cords are all test- and quality-assured, provided at affordable prices, available in various kinds, like LC fiber cable, SC patch cord, LC SC cable, ST ST fiber cable, and so on. If you want such products, please visit Fiberstore directly.