Fibre optic systems are used where mounting space for photoelectric standard sensors is restricted. The evaluation unit and the fibre optics are mounted separately. These systems can therefore be installed in places where access is difficult.

Fibre optic systems are designed as through-beam or diffuse reflection sensors.

Silicate glass fibre optics for temperatures up to 150 °C come equipped with a metal silicone sheath. The sheathing for high-temperature applications, as they occur in the steel or glass industries, is made of aluminium (up to 290 °C) or stainless steel (up to 315 °C).