Use of LEDs as a light receiving component and their application to demonstration experiments for educational purposes

Light emitting diodes (LEDs) can be used as a light receiving component which is less likely to be saturated than photodiodes. The author has actually employed LEDs for the purpose of receiving optical signals in demonstration experiment sets of optical communication for educational purposes targeting elementary school to high school students. By using LEDs both for a light emitting component and a light receiving component, relationships among color of light (wavelengths or frequencies) and their energies as well as bandgap energies of semiconductor materials can be explained in such demonstration.