Low-loss single-material fibers made from pure fused silica

Low-loss single- and multimode optical fibers were fabricated solely from pure fused silica. Their spectral losses corresponded closely to those of unclad fibers drawn from the same material, provided the cores of the single-material fiber preform were redrawn under pure conditions. The lowest steady-state loss of about 3 dB/km at a wavelength of 1.1 μm was obtained with a fiber 130 meters long that had a Spectrosil WF core. Experimental numerical apertures agreed excellently with theoretical predictions.