The spectral window of mixed AgClxBr1-x (0≤x≤1) crystals and polycrystalline fibers was investigated as a function of composition. Both visible edge, resulting from electronic transitions, and infrared edge due to multiphonon processes, behave as the one-mode (amalgamation) type of mixed crystals, shifting continuously with composition. The extruded polycrystalline optical fibers preserve the spectral window of silver-halide crystals. Deviations which slightly broaden the window in the infrared regime are explained by the fibers small-grain structure.