Fiber optic transmission takes place in what portion of the spectrum?

Fiber optic transmission primarily takes place in the infrared portion of the electromagnetic spectrum. This is because optical fibers are designed to transmit light signals, which in this case are near-infrared wavelengths. Specifically, standard single-mode and multi-mode fibers typically operate in the range of 1260 to 1550 nanometers (nm), which falls within the infrared range.

The use of infrared light is advantageous because it allows for lower absorption losses and higher transmission distances in optical fibers. Infrared wavelengths are ideal for data transmission due to their ability to propagate through glass with minimal loss and interference, enabling high-speed data transfer over long distances, which is a critical requirement in modern telecommunications and networking.

The other options do not pertain to the light used in fiber optics; ultraviolet light, while it can transmit data, is generally not used in fiber optics due to its higher attenuation and potential damage to the fiber material. Subsonic refers to sound waves traveling below the speed of sound and is irrelevant to light transmission in fiber optics. Thus, infrared is the correct answer for the portion of the spectrum utilized in fiber optic transmission.