Signal transmission systems

摘要

A signal transmission system impresses phase-modulated signals on to a multimode optical fibre waveguide 1. In order to overcome the effects of fading caused by small random changes in the parameters of the fibre the signals from different modes are all combined to derive a resulting signal which is detected in a common detector 23. The signals may be combined by a vibrating mirror 21 which sweeps the emergent beam across detector 23. Alternatively the tip of fibre 1 may be vibrated to achieve a similar effect.