What is a photodetector used for in fiber optics?

A photodetector plays a crucial role in fiber optics by converting optical signals back into electrical signals. This process is essential for the functioning of fiber optic communication systems, where data is transmitted as light pulses through the fiber. The photodetector captures these light pulses emitted from a light source, such as a laser or LED, and translates them into electrical current or voltage that can be processed by electronic equipment.

This conversion is vital because, while fiber optics is excellent for transmitting information over long distances with high bandwidth, the end devices that process this information, like computers and other electronic systems, operate using electrical signals. The accurate and efficient functioning of the photodetector ensures that the data being transmitted through the fiber optic cables can be reliably received and interpreted.

The other options do not align with the primary function of a photodetector in fiber optics. Amplifying signals pertains more to devices like optical amplifiers, while providing illumination is unrelated to the core function of detecting and converting signals. Detecting faulty connections may involve other types of diagnostic equipment rather than the photodetector itself, which focuses on the signal conversion process.