Abstract
This research focuses on the performance analysis and characterization of a fiber Bragg gratings (FBGs) array, consisting of 10 first order FBGs inscribed by a femtosecond (FS) laser in a highly multimode coreless fiber. The study evaluates the FBG array's ability to function as a distributed thermal sensing (DTS) platform, with the coreless fiber chosen as the sensing element due to its immunity to dopant migration at high temperatures. The design of a large cascaded first-order FBG array effectively eliminates unwanted harmonic peaks across a wide spectrum range. In contrast, higher-order FBGs introduce limitations due to the overlapping of Bragg peaks with harmonics. The FBG array's performance is evaluated by measuring the reflection spectrum of each grating at different temperatures, showing a high temperature sensitivity of 15.05 pm/°C at a Bragg wavelength of 1606.3 nm, with a linear response in the temperature range of 24 - 1100 °C. The FBG array was designed for a spatial resolution of 5 mm. A mode scrambler in the sensing network is employed, which suppresses multimodal interference, characterizes FBG peak visibility, and stabilizes the interference spectrum. The stability of the FBG array is also assessed over 24 hrs. at 1100 °C, and it is observed to be stable during thermal treatment. Heat treatment at 1100°C improves the signal to noise ratio of the FBG array, demonstrating the robustness and suitability of the proposed FBG array on highly multimode coreless fiber as a potential sensing platform for DTS applications in harsh environmental conditions, overcoming the issues of dopant migration presented by dopes silica optical fibers at high temperatures.
Recommended Citation
F. Mumtaz et al., "Large-scale Cascading Of First-order FBG Array In A Highly Multimode Coreless Fiber Using Femtosecond Laser For Distributed Thermal Sensing," Optics express, vol. 31, no. 18, pp. 29639 - 29653, Optica Publishing Group, Aug 2023.
The definitive version is available at https://doi.org/10.1364/OE.494092
Department(s)
Electrical and Computer Engineering
Second Department
Materials Science and Engineering
Publication Status
Open Access
International Standard Serial Number (ISSN)
1094-4087
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2024 Optica Publishing Group, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
28 Aug 2023
PubMed ID
37710760
