How to use the red light source of a fiber optic test pen

It works by injecting a visible red laser light (usually in the 650nm wavelength) into the fiber. When the light encounters a fault, such as a break, bend, or bad splice, it leaks out of the fiber, making the fault visible to the naked eye. When it comes to testing fiber optic cables, a Visual Fault Locator (VFL) is an essential tool in your toolkit., optical fiber fault detector, optical fiber fault test pen) is a 650nm (± 20nm) semiconductor laser as a light-emitting device, which emits stable red light through a constant current source drive, and connects with the optical interface into the optical fiber, so. A Visual Fault Locator which can be also called visual fault identifier (VFI), f...