Fiber optic cable is tested to ensure continuity and attenuation. Basically, there are three methods commonly performed for optical fiber testing: visible light source, power meter and light source (one jumper method), and optical time domain reflectometer (OTDR). Key tests include: Effective fiber testing utilizes advanced tools such as Optical. We'll explain why it's vital to test fiber optic cables, the three most popular methods, and when you should use them. That process, thankfully, is a simple one.