Sensors (Jan 2020)

Low-Finesse Fabry–Pérot Interferometers Applied in the Study of the Relation between the Optical Path Difference and Poles Location

  • José Trinidad Guillen Bonilla,
  • Héctor Guillen Bonilla,
  • Verónica María Rodríguez Betancourtt,
  • María Eugenia Sánchez Morales,
  • Juan Reyes Gómez,
  • Antonio Casillas Zamora,
  • Alex Guillen Bonilla

DOI
https://doi.org/10.3390/s20020453
Journal volume & issue
Vol. 20, no. 2
p. 453

Abstract

Read online

Interferometry sensors are frequently analyzed by applying the Fourier transform because the transformation separates all frequency components of its signal, making its study on a complex plane feasible. In this work, we study the relation between the optical path difference (OPD) and poles location theoretically and experimentally, using the Laplace transform and a pole-zero map. Theory and experiments are in concordance. For our study, only the cosine function was considered, which is filtered from the interference pattern. In experimental work, two unperturbed low-finesse Fabry−Pérot interferometers were used. First, a Fabry−Pérot interferometer that has a cavity length of ~ 1.6 mm was used. Its optical path difference was 2.33 mm and the poles were localized at points ± i 12 . rad/nm. Secondly, a Fabry−Pérot interferometer with a cavity length of ~ 5.2 mm was used, and its optical path difference was 7.59 mm and the poles were localized at points ± i 40.4 rad/nm. Experimental results confirmed the theoretical analysis. Our proposal finds practical application for interferometer analysis, signal processing of optical fiber sensors, communication system analysis, and multiplexing systems based on interferometers.

Keywords