TY - GEN
T1 - Exploring the use of a virtual reference spectrum in the Vernier effect
AU - Santos, Daniela
AU - Gonçalves, Gil
AU - Marques, Paula A.A.P.
AU - Domingues, M. Fátima
AU - Antunes, Paulo
AU - Ferreira, Marta S.
AU - Alberto, Nélia
N1 - Publisher Copyright:
© 2025 SPIE.
PY - 2025
Y1 - 2025
N2 - The optical Vernier effect (OVE) has been widely exploited as a method to enhance the sensitivity of interferometric optical fiber sensors. This is usually achieved by cascading or paralleling two interferometers, one as sensing element, and other as reference. Here it is explored the use of a single interferometer, which detects the changed signal, and a virtual reference spectrum to be superimposed with the sensing optical signal, realizing the OVE. Open Fabry-Perot interferometer (FPI) cavities with different lengths (Lsens from 118 to 539 μm) are characterized to refractive index (RI) variations, using glucose solutions with varying concentrations. One of the sensors with the highest sensitivity (Lsens= 292 μm) is chosen for further exploration of the OVE. Using the optical spectrum obtained when this sensor was immersed in water, virtual reference optical spectra corresponding to FPIs with different lengths (Lref from 320 to 390 μm) are simulated, using, in this case, the OriginPro software. Once the most suitable conditions are chosen, the behavior of the spectral overlap is evaluated, and the sensing magnification resulting from the OVE application is determined. A sensitivity of (20562 ± 1461) nm/RIU is achieved, which corresponds to a magnification factor, M = 14.1. The use of a virtual reference signal in the OVE is a simpler and more economical approach, with the possibility to adjust the magnified sensitivity.
AB - The optical Vernier effect (OVE) has been widely exploited as a method to enhance the sensitivity of interferometric optical fiber sensors. This is usually achieved by cascading or paralleling two interferometers, one as sensing element, and other as reference. Here it is explored the use of a single interferometer, which detects the changed signal, and a virtual reference spectrum to be superimposed with the sensing optical signal, realizing the OVE. Open Fabry-Perot interferometer (FPI) cavities with different lengths (Lsens from 118 to 539 μm) are characterized to refractive index (RI) variations, using glucose solutions with varying concentrations. One of the sensors with the highest sensitivity (Lsens= 292 μm) is chosen for further exploration of the OVE. Using the optical spectrum obtained when this sensor was immersed in water, virtual reference optical spectra corresponding to FPIs with different lengths (Lref from 320 to 390 μm) are simulated, using, in this case, the OriginPro software. Once the most suitable conditions are chosen, the behavior of the spectral overlap is evaluated, and the sensing magnification resulting from the OVE application is determined. A sensitivity of (20562 ± 1461) nm/RIU is achieved, which corresponds to a magnification factor, M = 14.1. The use of a virtual reference signal in the OVE is a simpler and more economical approach, with the possibility to adjust the magnified sensitivity.
KW - Fabry-Perot interferometer
KW - magnification factor
KW - sensing cavity
KW - Vernier effect
KW - virtual reference spectrum
UR - https://www.scopus.com/pages/publications/105007936007
U2 - 10.1117/12.3062037
DO - 10.1117/12.3062037
M3 - Conference contribution
AN - SCOPUS:105007936007
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - 29th International Conference on Optical Fiber Sensors
A2 - Santos, Jose Luis
A2 - Sainz, Manuel Lopez-Amo
A2 - Sun, Tong
PB - SPIE
T2 - 29th International Conference on Optical Fiber Sensors
Y2 - 25 May 2025 through 30 May 2025
ER -