Abstract

This paper reports a sensitivity-improved fiber Bragg grating (FBG) sensor system based on microwave-photonic interferometry and the Vernier effect. an incoherent microwave photonics system based on a broadband light source is employed to interrogate the FBG sensor using the wavelength-to-delay mapping technique combined with interferometry. Specifically, the sensing FBG together with a reference FBG is used to construct a microwave photonics Michelson interferometer (MI). Changes in the Bragg wavelength of the sensing FBG subject to external perturbations are encoded into the spectral shifts of the microwave interferogram of the MI. a virtual interferometer is then generated from the sensing MI based on a computational Vernier effect modality. by superimposing the spectra of the sensing MI and the virtual interferometer, the Vernier effect is generated. by tracking the spectral shift of the Vernier envelope, it is shown that the measurement sensitivity of the sensing FBG is remarkably enhanced with an expected factor. Moreover, a quasi-distributed sensor system with enhanced sensitivity based on cascaded FBGs and the proposed virtual microwave-photonic Vernier effect technique is implemented, representing the first demonstration of a Vernier effect-enhanced FBG array sensor. Additionally, the possibility of employing the harmonic Vernier effect for further sensitivity enhancement is investigated, where a remarkable sensitivity enhancement factors up to 685 with a strain sensitivity of 94 MHz/µε is successfully demonstrated.

Department(s)

Electrical and Computer Engineering

Publication Status

Open Access

Comments

Ministry of Education – Kingdom of Saudi Arabi, Grant IFKSUOR3-261-2

International Standard Serial Number (ISSN)

1094-4087

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2025 Optica Publishing Group, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

04 Dec 2023

PubMed ID

38087584

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