Connect a visible light source (such as a fiber optic flashlight) to one end of the cable. Fiber optic cable is a type of cabling that contains one or more optical fibers for transmitting data at high speeds and/or over long distances using light. These fibers are most commonly made of glass and are very thin, typically less than a tenth of the width of a human hair. Fiber optic cable. Here are some steps for testing single mode fiber optic cable: Step 1: Gather equipment To test a single mode fiber optic cable, you will need the following equipment: - Light source: a device that emits a specific wavelength of light to allow detection of any breaks or faults in the fiber optic. Fiber optic loss testing is an essential part of maintaining reliable, high-performance fiber optic networks because it helps identify potential issues and ensures that the system meets the required performance specifications. In this blog, we'll explore what a power meter and light source are and. 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).