Coherent optical-fibre communication system using polarisation-diversity transmission.

摘要

A coherent optical-fibre transmission system is rendered insensitive to fluctuations of the state of polarisation of the electromagnetic field due to propagation along the fibre by varying at the transmitting side the state of polarisation of the optical carrier modulated by the information signal to be transmitted. The variation is such that spectral broadening of the intermediate frequency signal at the receiver is kept limited, while reception of half the power outgoing from the fibre is ensured. <IMAGE>