Limitation of transmission distance and capacity due to polarisation dispersion in a lightwave system

Abstract

The length dependence of group delay differences between orthogonally polarised modes has been investigated experimentally for real single-mode fibres ranging from 0.1 km to 100 km. The mean group delay difference is a constant value of 0.67 ps, over a length of more than 1 km. The mode coupling coefficient of random mode mixing which causes pulse broadening has been estimated to be 6.3 × 10−3m−1. A light pulse will broaden by 17 ps after traversing a 100 km-long fibre. This may restrict single-mode fibre systems to a bit rate of 10 GHz for lengths over 150 km.