Improving the bandwidth of optical fibers made using modified CVD

High-bandwidth multimode fibers are made with index profiles that can be approximately described by the a law: Δ(r) = Δ(0)[ 1 — (rla)“], with Δ(r) = [n(r) — n0]/n(0), n0 the index of the cladding, and a the core radius. Fibers with such profiles have been shown both theoretically and experimentally to have sharply peaked spectral bandwidth characteristics. Here we discuss methods for increasing the bandwidth of such fibers and for altering the high-bandwidth spectral region to meet changing system requirements, for example, a new operating wavelength or introduction of wavelength multiplexing.