In a fiber optic link, which component primarily generates the light used to carry the signal?

• A. Photodetector
• B. Transmitting Device
• C. Optical Receiver
• D. Power Supply

Answer: (B)

In a fiber optic link, light must be created first to carry the data. The transmitting device houses the light source, such as a laser diode or LED, and the circuitry that modulates it with the electrical signal. This combination is what actually generates and launches the optical signal into the fiber. The photodetector at the receiving end is what detects that light and converts it back to an electrical signal, while the optical receiver handles processing of the incoming signal. The power supply simply provides power to the system; it doesn’t generate the light. So the component that primarily generates the light used to carry the signal is the transmitting device.