Monomode optical fibre with ramped refractive index profile - has continuous linear increase in index of inner cladding up to intermediate value of core index

摘要

The core, which in conventional fibres has an abrupt transition to a lower refractive index at its interface with the cladding, is made significantly smaller with an actual dia. (2a) only 10/11 of the max. (2a'). The max. difference (delta n+) in refractive index between core and cladding is 0.00401 and the cladding proper has a refractive index (delta n-) reduced by 0.0012. This is achieved by doping with P and F alone in the inner cladding. ADVANTAGE - Fibre having less attenuation and sensitivity to curvature can be mfd. easily with smaller requirements of Ge and P.