What are the three most common wavelength bands used for communications through optical fibers?

The three most common wavelength bands used for communications through optical fibers are indeed 850 nm, 1300 nm, and 1550 nm.

These wavelengths are significant due to their effectiveness in minimizing loss and maximizing the data transfer capabilities of optical fibers.

At 850 nm, multimode fibers are typically used, making this wavelength ideal for short-distance applications such as local area networks. The light at this wavelength tends to move well within the core of multimode fibers, thus providing an effective solution for these specific communication needs.

The 1300 nm wavelength is often associated with both multimode and single-mode fibers, supporting longer distances better than the 850 nm wavelength. It offers a good balance between performance and loss, making it a preferred choice for many installations that require greater distance without significant signal degradation.

The 1550 nm wavelength is critical in long-haul communication systems, especially in single-mode fiber applications. This wavelength region takes advantage of the reduced attenuation and low signal loss characteristics of optical fibers, allowing it to efficiently transmit signals over tens of kilometers without the need for repeaters.

Thus, these three wavelengths are prominent in fiber optic communication due to their unique advantages in different fiber types and varying transmission distances.