Abstract

Recently we reported on a new type of low-loss, large-numerical- aperture optical fiber consisting of a pure fused silica core loosely surrounded by an extruded cladding tube of a low-index polymer. Teflon PEP (PEP).¹ One of the difficulties encountered in that work was the presence of large diameter variations of the oxy-hydrogen-torch-drawn fibers, which resulted in the coupling of well-guided modes to lossy radiation modes. In order to avoid this difficulty, we used a CO₂ laser for the drawing operation which has been demonstrated to produce contamination-free fibers with good diameter control.²

© 1975 Optical Society of America