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

Abstract

The factors limiting the resolution of displacement sensors based on the extrinsic Fabry-Perot interferometer were studied. An analytical model giving the dependency of extrinsic Fabry-Perot interferometric (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 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 of microns to 5 mm), a high baseline resolution (from 14 pm), and good agreement with the model.

Utilization of NI PXIe-4844 interrogator for high resolution fiber extrinsic Fabry-Perot interferometric sensing

“…The analysis of the influence of these parameters on the resultant sensor resolution is complicated since this influence depends on the properties of the interrogator, such as Λ и Δ and on the parameters of the optical scheme. Analytical expressions, relating the quantity σ Lr with the optical setup parameters were obtained by the authors in [7]. Experiments, supporting the developed model were performed, demonstrating very good correspondence with the theory.…”

“…Second approach demonstrated subnanometers resolutions of OPD measuring, high absolute accuracies and large dynamic measurement range [3]- [6]. The best examples of attained OPD resolutions, were attained using wavelength scanning approach, and equaled 10 pm [7].…”

“…Fluctuations of the interrogator parameters can be one of the main fundamental factors, limiting the resolution δL min [7]. When using the above-mentioned approach, one of the most important parameters are: the shift of the whole wavelength scale, jitter of individual spectral points; intensity noises of the light source and photodetector noises.…”

“…2. OPD measurement resolutions for different reflectivity of the second mirror (first mirror R 1 =3,5%); experimental (points) and theoretical, calculated according to [7] (solid curves)…”

Optical properties of metallic nanoparticles trapped by arabinogalactan molecule

“…A calibration curve relating the interferometer spectrum fringe visibility with the refractive index of the medium at the right side of the plate is shown in figure 2. The curve was calculated analytically with the use of the Gaussian beam formalism, applied to the Fabry-Perot cavity 9 . The cavity parameters were substituted the same as the practical (L 0 =240 μm, silicon inside the cavity).…”