Shifted dispersion single mode fibre optic index doping technique; has central triangular, rectangular or trapezoidal profile and outer sheath region with specific inner doped region and higher doped outer region sections

摘要

The fibre optic cable construction has a central core and an outer sleeve with a doped index profile. The core of the cable has a trapezoidal, triangular or rectangular index profile (n1). The outer ring has a first doped index region (n2). There is a second index level in the outer section with an index level (n3) over a region above that of the first outer ring doping region.