Since their inception in the 1970s, fiber optic networks have continually evolved and expanded. The emergence of 5G, submarine networks, and FTTH (Fiber to the Home) have highlighted the importance of robust fiber testing and monitoring. Testing fiber optic networks is an essential part of fiber optic installation, as well as ongoing maintenance. Following some fundamental fiber testing best practices will lead to safer, more efficient, and more reliable fiber deployments and network activation.

 

• The importance of cleanliness in fiber installation and testing cannot be overstated. A fiber optic microscope can be used as a fiber optic tester to verify the cleanliness of the core and connecting ferrules. Automated inspection tools can be used for common fiber interfaces like PON and MPO. Specialized cleaning materials are recommended for proper cleaning of fiber optic connections. This same attention to cleanliness should be applied to reference cables and test equipment connections.

• When using a VFL (Visual Fault Locator) fiber tester for fault location, eye safety is extremely important. Since a VFL utilizes a high-intensity laser light source, neither the source nor the fiber core illuminated by the VFL should be viewed directly with the naked eye.

• The use of an optical light source and a power meter, or an optical loss test set (OLTS), is considered a good fiber test practice for ensuring that the optical power budget is within design specifications. A calibrated optical light source (OLS) can be used in conjunction with an optical power meter (OPM) to quantify the insertion loss of the link prior to turn-up.

• An OTDR is the recommended fiber optic test tool for detailed baselining and recording of fiber link ‘characteristics’.

• The purpose of an OTDR is to detect, find, and measure events at any location on a fiber link. Location information regarding localized loss and reflective events is generated, providing technicians with a pictorial and permanent record of the fiber’s characteristics.

• When using an OTDR, use launch cables to qualify the front-end and far-end connectors. A launch cable is connected between a tester and the fiber under test, and the receive cable is connected at the far end of the fiber link. It is important to note that the fiber used in the launch and receive cable should match the fiber being tested (type, core size, etc.)

• Test process automation (TPA) principles that are effective on the production floor can also be extended to fiber network installation. By minimizing manual test processes and reducing opportunities for errors and training time, certification and turn-up can be completed and documented confidently and predictably.

• Lastly, proper planning and preparation are basic best practices applicable to any organized endeavor, including fiber testing. Assembling and organizing a pre-cleaned, calibrated, and complete test tool kit is essential for carrying out the most effective and accurate fiber optic tests.