FIELD: fiber optics. SUBSTANCE: invention relates to applications in various fields of special fiber optics based on infrared (IR) fiber assemblies, made of photo- and radiation-resistant light guides of new system AgBr – (TlBr0.46I0.54). Method of producing fiber assemblies based on polycrystalline infrared light guides, including their packaging in an assembly, characterized in that the light guides of the polycrystalline structure are made from AgBr – (TlBr0.46I0.54) system monocrystals by cutting a workpiece with diameter of 13.0–15.0 mm, height of 24.0–34.0 mm. Then by means of extrusion method one-layer billet is produced with grain size of 700.0–800.0 nm, diameter of 3.0 mm, length of 645.0±5 mm and secondary extrusion to produce nanocrystalline light guide with grain size of 70.0–80.0 nm, with diameter of 90.0 mcm, length of 675.0±1 m, which is cut into light guides with length of 4.0–5.0 m, and mechanical laying of 7; 37; 91 light guides form hexagonal assemblies with their subsequent compaction, wherein the diameter of assemblies is 210; 630; 990 mcm, wherein the light guides contain ingredients in the following ratio, wt%: silver bromide 95.0–60.0; TlBr0.46I0.54 solid solution 5.0–40.0. EFFECT: high spatial and temperature resolution of fiber assemblies.