Which wavelengths are typically used for long-distance transmission in fiber optics?

The selection of wavelengths 850 nm, 1300 nm, and 1550 nm is appropriate for long-distance transmission in fiber optics due to their intrinsic properties that support efficient signal travel over extended distances.

At these wavelengths, the fiber optic materials—typically silica—have low attenuation, meaning that the signal degrades minimally as it travels through the fiber. Specifically, 850 nm is commonly used for short to moderate distances, such as in local area networks, while 1300 nm and 1550 nm are favored for longer distances due to even lower loss rates. The 1550 nm wavelength is particularly optimal for long-haul communications because it allows for the use of standard erbium-doped fiber amplifiers, which can amplify signals without needing to convert them to electrical signals.

In contrast, the other options present wavelengths that are either too short or not commonly utilized for long-distance transmission in fiber optics. Wavelengths below 850 nm generally suffer from higher attenuation in standard silica fibers, making them unsuitable for long-distance applications.