摘要 |
Cladded halide optical fibres for infrared transmission are made by covering a two-part halide compound billet (15), comprising a core (10), and a sleeve (8), with a polymer layer (12), heating the assembly and drawing it through a die (14). The halide compound forming the sleeve (8) has a lower refractory index than the halide compound forming the billet core (10). A second polymer layer (31) can be provided between the respective halide compounds. |