Prices typically range from about $0. 50 per foot for fiber optic cable and basic installation, depending on indoor vs outdoor routing, distance, and terrain. Single-mode fiber costs less per foot than multimode fiber, but it requires more. Underground fiber optic cable is designed for direct burial or conduit installation and is widely used in FTTH networks, backbone infrastructure, and industrial communication systems. This guide explains underground fiber optic cable types, installation methods, burial depth, and practical. Directly buried fiber optic cable is a kind of fiber optic cable armored with steel tape or steel wire, which can be resisting external mechanical damage and soil erosion, and can be buried directly into the ground.