Position-deviation-compensation demodulation method for multi-channel polarized low-coherence interferometry.

A position-deviation-compensation demodulation method is proposed to improve the channel adaptability of Fabry-Perot (F-P) sensor in a multi-channel optical fiber F-P sensing system. By combining the envelope peak position (EPP) retrieval process and the position compensation process, the proposed method enables the accurate demodulation of F-P sensors in all channels. Thereinto, the EPP retrieval process uses the phase information to recover the EPP with high precision; the position compensation process compensates the position deviation by an optical-path-based model, which is established to illustrate the principle of the position deviation between different channels. We carried out the pressure experiment to verify the effectiveness of the proposed method. The experiment results showed that the demodulation errors of all channels are no more than 0.13 kPa, which demonstrated that our approach is reliable for improving the channel adaptability of F-P sensors.