Multiplexed optical fibre interferometers: an analysis based on radar systems

This paper discusses an analytical technique whereby the potential performance of a multiplexed optical fibre interferometer system may be assessed. The approach exploits the very close analogies which may be drawn between such a system and a microwave radar. The importance of the optical waveform produced by the source used to illuminate the interferometer is demonstrated by its influence on the achievable resolution of the interferometer array for both dynamic (AC) and static (DC) measurements. The former are seen to be analogous to Doppler measurements in radar, and the latter to resolution in range. This comparison leads to the application of the concepts of ambiguity diagrams to optical systems. The source waveform is demonstrated to be a fundamental limiting factor on the performance of a multiplexed interferometer, as may be required in, for instance, a fibre sensor array.