Which tool is primarily used for detecting faults close to the end of a fiber optic cable?

The visual fault locator is specifically designed for identifying faults in fiber optic cables by emitting a bright light, typically laser, which can be seen through the fiber. When there is a break or defect in the fiber, the light will not transmit properly, making the issue visible. This feature allows technicians to quickly pinpoint the location of faults, especially those that are near the end of the cable.

In contrast, other tools like power meters, light sources, and launch cables serve different purposes in the realm of fiber optics. Power meters are used to measure the power level of a signal transmitted through the fiber, which helps determine overall performance rather than locate specific faults. Light sources provide a consistent signal to test the fiber, but they do not help in visually identifying breaks or imperfections. Launch cables are mainly used to minimize connection loss when testing, but they do not provide direct visual indications of faults like a visual fault locator does. Thus, the effectiveness of the visual fault locator in directly revealing faults makes it the preferred tool for this specific purpose.