| 摘要 |
A modulator arrangement adapted to use a differential quadrature phase shift key for use in an optical wavelength division multiplex (WDM) optical communications system, comprising a precoder ( 16 ), which is adapted to generate drive voltages for first and second phrase modulators ( 6, 8 ) in dependence upon first and second data streams. The respective drive voltages for the first and second modulators ( 6, 8 ) are fed back to the precoder inputs with a delay related to the line speed of the data system, wherein the length of the delay corresponds to n bits. |
