Which type of fiber optic cable is least susceptible to external environmental conditions?

Armored fiber is specifically designed to withstand harsh external environmental conditions. It is encased in a protective layer that typically includes materials like steel or other robust substances, which provide resistance against physical damage, moisture, chemicals, and other environmental factors. This added protection allows armored fiber to be installed in outdoor settings or locations where it might be exposed to potential harm, such as construction sites or industrial environments, making it less susceptible to damage compared to other types of fiber optic cables.

In contrast, plastic optical fibers, while flexible and lightweight, are generally more vulnerable to environmental factors due to their materials and construction. Single-mode and multimode fibers, although effective in transmitting data and designed for specific applications, lack the additional protective features that armored fiber provides, making them more exposed to potential damage. These characteristics highlight why armored fiber stands out as the most robust option when considering external environmental susceptibility.