Single-Mode Optical Fiber Technology II. Silica-Based Single-Mode Fiber Technology, Loss and Polarization Properties

Abstract

In silica-based fiber technology four different processes are actually used on a routine basis for preform manufacturing: the outside vapour phase oxidation processes (OVPO), a special version of which is the vapour phase axial deposition process (VAD), and the inside vapour phase oxidation process (IVPO), based either on modified chemical vapour phase deposition (MCVD) or on plasma activated chemical vapour phase deposition (PCVD). Only the VAD process yields a massive but porous rod. In the other three methods a hollow tube is produced, from which the preform is obtained by collapsing for MCVD and PCVD. With OVPO the hole disappears upon drawing. Drawing technology will be discussed in the next lecture, where the double-crucible method will be considered. Each of these fabrication techniques has its own typical advantages and disadvantages, the relative merits of which can only be assumed with respect to a specified requirement. In this lecture the yardstick is their capability to produce single-mode (SM) fibers economically. SM fibers are attractive as future high-capacity, long-distance transmission lines with low-loss and hence large repeater distances.