Summary

Recommendation ITU-T G.656 describes the geometrical, mechanical, and transmission attributes of a single-mode optical fibre which has the positive value of the chromatic dispersion coefficient greater than some non-zero value throughout the wavelength range of anticipated use 1460‑1625 nm. This dispersion reduces the growth of non-linear effects which are particularly deleterious in dense wavelength division multiplexing systems.

This fibre can be used for both CWDM (coarse wavelength division multiplexing) and DWDM (dense wavelength division multiplexing) systems throughout the wavelength region between 1460 and 1625 nm.

Edition 2 limits the chromatic dispersion coefficient by a pair of bounding curves vs wavelength for the range of 1460 nm to 1625 nm, which provides information to support CWDM and DWDM applications.

Edition 3 removes jumper cut-off wavelength definition and adds a note allowing higher maximum cabled attenuation for short jumper cables.