ITU-T G.657 PDF

This Recommendation describes two categories of single-mode optical fibre cable which are suitable for use in the access networks, including inside buildings at the end of these networks. Both categories A and B contain two sub-categories which differ in macrobending loss.

Category A fibres are suitable to be used in the O, E, S, C and L-band (i.e., throughout the 1260 to 1625 nm range). Fibres and requirements in this category are a subset of ITU-T G.652.D fibres and have the same transmission and interconnection properties. The main modifications are improved bending loss and tighter dimensional specifications, both for improved connectivity. Sub-category ITU-T G.657.A1 fibres are appropriate for a minimum design radius of 10 mm. This sub-category encompasses fully the former ITU-T G.657(12/2006).A category.

Sub-category ITU-T G.657.A2 fibres are appropriate for a minimum design radius of 7.5 mm.

Category B fibres are suitable for transmission at 1310, 1550 and 1625 nm for restricted distances. These fibres may have different splicing and connection properties than ITU-T G.652 fibres, but are capable at very low values of bend radius.

Sub-category ITU-T G.657.B2 fibres are appropriate for a minimum design radius of 7.5 mm. This sub-category encompasses fully the former ITU-T G.657(12/2006).B category.

Sub-category ITU-T G.657.B3 fibres are appropriate for a minimum design radius of 5 mm.

The meaning of the terms used in this Recommendation and the guidelines to be followed in the measurement to verify the various characteristics are given in [ITU-T G.650.1] and [ITU-T G.650.2]. The characteristics of these fibre categories, including the definitions of the relevant parameters, their test methods and relevant values, will be refined as studies and experience progress.