The three standard methods for testing fiber optic cabling are a visible light source, power meter and light source, and optical time domain reflectometer (OTDR). Fiber Optic Testing Testing is used to evaluate the performance of fiber optic components, cable plants and systems. Key tests include: Effective fiber testing utilizes advanced tools such as Optical. Learn all about fiber testing including testing fiber for optical loss and optical speed as well as fiber testing best practices and procedures.