Which component senses light in the optical receiver path?

• A. Transmitter
• B. LED
• C. Photodiode
• D. Photovoltaic Cell

Answer: (C)

In an optical receiver path, the component that senses light is a photodetector that converts incident light into an electrical signal. The photodiode is specifically designed for fast response and high sensitivity, making it ideal for extracting the data carried by the light. When light from the fiber hits the photodiode, it generates a photocurrent proportional to the light intensity, which is then fed into a transimpedance amplifier to produce ausable voltage for processing. The transmitter path, including the transmitter itself and LEDs, provides the light source but does not detect light. A photovoltaic cell can detect light as well, but it’s generally slower and not optimized for the high-speed, telecom-type wavelengths used in optical receivers, so it isn’t used in the receiver path.