Epoxy-acrylate-coated fused silica fibers with tensile strengths ≳500 ksi (3.5 GN/m2) in 1-km gauge lengths

Abstract

Laser‐drawn epoxy‐acrylate‐coated fused silica fibers (∼110 μm fiber diameter) have been produced with high and exceptionally uniform strength. When tested in 20‐μm lengths, they show a single‐moded Weibull distribution, (m∼25), a median tensile strength S_m of 750 ksi (5.25 GN/m²), and a coefficient of variation (ν) of about 0.04. Using the previously justified ’’weakest link’’ model, this predicts S_m∼600 ksi (4.2 GN/m²) for l‐km gauge lengths. The measured strength of a 1680‐m‐long fiber (i.e., the minimum strength found in testing 84 20‐m lengths) is 620 ksi (4.35 GN/m²). The capability of drawing kilometer lengths of fibers with strengths of this magnitude and uniformity is extremely important for the production of optical fiber cables.