English: Experimental attenuation curve of low loss multimode silica (Thorlabs, blue line) and ZBLAN (Le Verre Fluoré, red line) optical fibers. Arrows highlight the four orders of magnitude improvement of silica single mode optical fiber attenuation over four decades: 1000 dB/km in 1965 down to 0.18 dB/km (theoretical limit) in 2002. By comparison, ZBLAN optical fibers current attenuation is ~1dB/km and can still be reduced three orders of magnitude to an estimated theoretical best about ~6.4•10-3 dB/km (red diamond). ATTRIBUTION: Cozmuta et al, "Breaking the Silica Ceiling: ZBLAN based opportunities for photonics applications"^[1]