When it comes to testing fiber optic cables, a Visual Fault Locator (VFL) is an essential tool in your toolkit. It's a cost-effective and. The state, throughput, and identification of an optical fiber can be easily checked with fiber testers by coupling highly visible laser light into the optical fiber. The red light of a laser is coupled into the core of an optical fiber in a targeted manner (an LED is usually too weak a source to be. Regularly testing fiber optic cables helps minimize network downtime, lengthens the network's longevity, reduces maintenance requirements, and helps support network reconfiguration and upgrades. Fiber optic testing of a newly installed system not only verifies that the system meets its design requirements, but also creates a performance baseline for all future testing and troubleshooting of t at system.