The use of coherent technology in unrepeatered optical systems

The capabilities of coherent detection for unrepeatered systems is outlined both in terms of components and subsystem performance and it is shown that the expected component improvements will make possible the realisation of coherent systems able to offer link lengths of around 300 km. As the component performance improves it is expected that the link length will increase by using either more efficient modulation formats or improving the initial 'weakly coherent' systems.<
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