Abstract

Fiber Bragg gratings (FBGs) have been one of the most widely used optical fiber sensors in both scientific and industrial applications due to their unique advantages of high sensitivity, ease of signal transduction, and capabilities for remote operation and multiplexing. However, the majority of sensing systems based on FBGs can only achieve quasi-distributed sensing along the fiber under test, leaving dark zones in between discrete FBG elements. In this work, we propose and demonstrate a microwave photonics enabled approach for the interrogation of cascaded FBGs to achieve spatially distributed sensing. The core of the system includes an incoherent optical frequency-domain reflectometry module, with the assistance of a dispersive element and a joint time-frequency domain demodulation strategy. By measuring the electrical frequency response of the FBG arrays, followed by the joint time-frequency domain analysis, both the FBG elements and the optical fiber sections connecting the FBGs can be used as sensor devices based on a wavelength-to-delay-mapping technique and interferometry, respectively. Proof-of-concept experiments with a 10-FBG array (10 cm spacing) demonstrated strain sensitivities of –2.37 kHz/μϵ (interferometric channel) and –0.335 ps/μϵ (wavelength-to-delay channel), corresponding to strain resolutions of ∼10 μϵ and ∼0.9 μϵ, respectively. The approach is further shown to support hybrid WDM–TDM interrogation, offering scalability and compatibility with weak FBG arrays.

Department(s)

Electrical and Computer Engineering

Publication Status

Early Access

Comments

University of Phayao, Grant None

Keywords and Phrases

Distributed sensing; fiber Bragg grating; fiber optic sensors; frequency response; microwave photonics

International Standard Serial Number (ISSN)

1558-2213; 0733-8724

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Institute of Electrical and Electronics Engineers; Optica Publishing Group, All rights reserved.

Publication Date

01 Jan 2025

Download

Full Text Link

Share

 
COinS