A reduction of interferometric phase-to-intensity conversion noise in fiber links by large index phase modulation of the optical beam

A noise reduction scheme for long haul fiber amplitude modulation (AM) systems is proposed and analyzed. Such systems suffer from intensity noise which results from interference between the (twice) Rayleigh scattered light and the directly transmitted beam. This interference converts the fundamental phase noise of the laser to intensity noise. It is shown that a strong phase modulation of the output of the laser beam causes a large reduction of the detected signal noise in the vicinity of the detected signal components.<
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