How are compound semiconductors used in lasers and optical-fibre communication?

Compound semiconductors, particularly III-V compounds such as gallium arsenide and indium phosphide, are essential for modern semiconductor lasers and optical fibre communication.12

Unlike silicon, these materials possess specific optical properties that allow them to emit light efficiently when forward-biased. By mixing elements like aluminum, gallium, indium, phosphorus, and arsenic, engineers can precisely tune the material's energy gap to produce light at specific wavelengths.132

In optical fibre systems, these lasers are critical because they can be modulated directly at high frequencies, enabling high-speed data transmission. Specifically, systems using layers of indium gallium arsenide phosphide and indium phosphide are used to generate light in the 1.3-micrometre and 1.5-micrometre ranges. These wavelengths are ideal because glass fibres exhibit very low transmission loss at these frequencies, making them the backbone of global telecommunications networks.1456