A method of making a dispersion managed optical cable installation, and cables for use in the method

摘要

A method of making an optical cable installation is characterised by the steps of: a) making optical fibre and cutting it to form at least one group of fibres with approximately equal fibre lengths suitable for making a length of cable; b) from the or each such group, measuring the chromatic dispersion value of each fibre and on the basis of that measurement allocating each fibre to a particular subgroup, there being subgroups distinguished by a different range of chromatic dispersion values that is narrow compared with the total range of chromatic dispersion values of the fibres in the group; c) marking each of the fibres to indicate the subgroup to which it belongs; d) making two cables of complementary length or two sets of cables of complementary aggregate length, each cable including at least one fibre from each of selected said subgroups; and e) connecting the fibres of these two cables or sets directly or indirectly according to the subgroups to which they belong so that the aggregate chromatic dispersion of each pair of connected fibres is within a single predetermined band and completing a dispersion-managed installation with at least one length of cable of opposite chromatic dispersion. The present invention provides a practicable and convenient method by which fibres can be selected and organised so that adequate dispersion management can be achieved with a fibre splices only at a small number of locations.