Resolution limits of extrinsic Fabry-Perot interferometric displacement sensors utilizing wavelength scanning interrogation

TL;DR

This paper develops an analytical model to determine the resolution limits of extrinsic Fabry-Perot interferometric displacement sensors using wavelength scanning, supported by experiments demonstrating high resolution and large measurement range.

Contribution

The paper introduces a new analytical model linking sensor resolution to optical setup parameters, aiding in sensor design and optimization.

Findings

Achieved a baseline resolution of 14 pm

Demonstrated a measurement range up to 5 mm

Model shows good agreement with experimental results

Abstract

The factors limiting the resolution of displacement sensor based on extrinsic Fabry-Perot interferometer were studied. An analytical model giving the dependency of EFPI resolution on the parameters of an optical setup and a sensor interrogator was developed. The proposed model enables one to either estimate the limit of possible resolution achievable with a given setup, or to derive the requirements for optical elements and/or a sensor interrogator necessary for attaining the desired sensor resolution. An experiment supporting the analytical derivations was performed, demonstrating a large dynamic measurement range (with cavity length from tens microns to 5 mm), a high baseline resolution (from 14 pm) and a good agreement with the model.