Pure silica, that is the base material commercial for single-mode optical fibres, has a maximum usability temperature of 1100°C, that is far beyond the needs of most D-FOS industrial applications. In standard fibres however, silica is always coated by some polymeric materials in order to protect it from surface scratches that are the main source of fibre mechanical failure, and such polymer coating is what restricts in practice the usable temperature range.

The typical temperature limits for polymers commonly used for fibre coating are:

Coating table.JPG