Test and Measurements

What Network Owners and Operators Need to Know About Fiber Testing


Certification of an FTTH network confirms proper installation before customers start using it. That means fewer service problems and easier routes to modifications. It also gives comfort to those who financed the build. Fiber test equipment makes testing and certification easy – often easier than for copper wiring.

Network testing and certification should be part of the contract for any network build. Following is what network owners, operators, technicians and installers need to know.

There are dozens of industry standards for which compliance has to be certified. Today, most test instruments, such as OTDRs and test sets, offer colorful screen displays and on-screen “wizards” that guide technicians step by-step through fiber certification tests for each standard. The instruments even calculate the thresholds – the levels needed to pass – for each situation.

This, of course, cuts technician errors and the time needed to run tests. Test equipment can even be upgraded to meet the latest, evolving standards. This emphatically does not mean technicians can go without training. But as a result of large FTTH builds ramping up after 2004, there is now a large cohort of technicians who can do the job.

To use a test set, for instance, a technician attaches a light source at one end of a network link. The source can be set to alternate between both test wavelengths (850/1300 nm for multimode fiber and 1310/1550 nm for single-mode). At the other end of the fiber span, the test device automatically synchronizes with the light source to perform a dual-wavelength insertion loss measurement in seconds. Sometimes it isn’t that simple – the technician may have to control the amount of light entering the fiber. Test devices can cover most conditions automatically, but there are always oddities.