Improving Rayleigh-limited bidirectional optical transmission systems by using time-slotting and frequency detuning

Two methods for improving Rayleigh-limited bidirectional transmission systems, carrier frequency detuning and time-slotting, are discussed and experimentally evaluated. Both methods are shown to provide arbitrarily small power penalty´s compared to unidirectional systems. It should be noted that the term time-slotting in this paper does not imply any synchronisation of the foward and backward going channels, only that the flow of light from the two transmitters aren´t continuous