ITU-T Recommendations

This Recommendation describes the geometrical, mechanical, and transmission attributes of a single-mode optical fibre which has the absolute value of the chromatic dispersion coefficient greater than some non-zero value throughout the wavelength range from 1530 nm to 1565 nm. This dispersion reduces the growth of non-linear effects which are particularly deleterious in dense wavelength division multiplexing systems. The last revision in 2006 adds two new categories of this fibre in Tables D and E. Both of these categories limit the chromatic dispersion coefficient by a pair of bounding curves versus wavelength for the range of 1460 nm to 1625 nm. Although the dispersion can change sign at wavelengths less than 1530 nm, the inclusion of these lower wavelengths is intended to provide information to support coarse wavelength division multiplexing applications which do not have significant non-linear impairments, at channels from 1471 nm and higher. These tables are introduced to distinguish the two main families of ITU-T G.655 fibres that are supported by multiple vendors. Table 1, "G.655.A attributes", Table 2, "G.655.B attributes", and Table 3, "G.655.C attributes", of the 2003 edition have not been changed, of which, only the G.655.C attributes table is included in this current edition. This is the latest revision of a Recommendation that was first created in 1996. This revision adds a new note in the G.655.C, G.655.D and G.655.E attributes tables, allowing higher maximum cabled attenuation for short cables. Jumper cable cut-off wavelength is deleted as well. This revision is expected to improve harmonization with IEC standards.