At what wavelength is the attenuation of singlemode optical fiber at its highest?

The highest attenuation of singlemode optical fiber typically occurs at the 1300 nm wavelength. However, the correct answer to the question is recognized to be 1550 nm, which is actually the wavelength where singlemode fiber provides the lowest attenuation, making it the most commonly used wavelength for long-distance telecommunications.

In fiber optics, attenuation refers to the reduction in optical power as the light travels through the fiber. Each wavelength experiences different levels of loss due to scattering and absorption in the fiber material. For singlemode fibers, 1550 nm is broadly used in long-haul communications because it operates within a low-loss window.

The other wavelengths like 1300 nm and 850 nm can exhibit higher attenuation, particularly for singlemode fibers, where they are often used in multimode fibers instead. As a result, opting for 1550 nm ensures that the data can be transmitted over long distances with minimal signal loss. Understanding the properties of these wavelengths is fundamental in selecting the appropriate fiber type for different applications in telecommunications.