CHARACTERISTICS OF PURE SILICA CORE SINGLE-MODE FIBER

There are two types of the SiO//2 core single-mode fiber. Type I fiber is fabricated by MCVD process and has a silica jacket in its outer cladding layer. Type II fiber is fabricated by VAD process. This fiber has a pure silica core and a cladding layer which consists of silica with fluorine uniformly added throughout the entire cladding region, achieves a 'matched cladding structure,' and has nearly the same fiber structural parameters as the conventional GeO//2-SiO//2 core fibers. This fiber is designed for use in both 1. 3 mu m and 1. 55 mu m wavelength. Some characteristics of practical use of the Type II fiber which we have developed are reviewed.