Polycrystalline infrared (PIR) fibers are used for numerous applications, one of those being power delivery for CO2 –lasers. However, the fiber tip surface’s transmittance cannot be increased with conventional antireflection coatings due to the surface unevenness. Antireflection microstructures (ARMs) offer an alternative way of increasing transmittance. In this work, ARMs were fabricated on the fiber tip surface of an AgClBr fiber by single-pulse femtosecond laser ablation. A single-surface transmittance of 92.8% at 10.6 µm, a CO2 –laser operation wavelength, was achieved. The proposed method can help significantly improve the systems’ efficiency, where power delivery for CO2 –lasers or sources operating in the wide wavelength range is required.