The interaction between fibre dispersion and laser phase noise in an ASK self-heterodyne millimetre-wave fibre-radio system

An analysis is presented of the BER achievable in an ASK modulated millimetre-wave self-heterodyne fibre radio system. The analysis shows that such systems require a depressed decision threshold if they are to exhibit optimum performance. This is due to the conversion of laser phase noise to intensity noise after the two optical carriers have experienced different delays due to propagation through the dispersive fibre. Results are presented that show the practicality of such systems over a very wide range of operating conditions.