Staff View: Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring

Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring

Pipelines undergo deformation leading to leakage several times throughout their service life. Hence, there is a need for Structural Health Monitoring (SHM) to ensure the safety of pipelines. Various conventional SHM and fiber optics technology methods for pipeline leakage detection have been explo...

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Main Author:	Onubogu, Nneka Obianuju
Format:	Final Year Project / Dissertation / Thesis
Published:	2023
Subjects:	S Agriculture (General) TA Engineering (General). Civil engineering (General)
Online Access:	http://eprints.utar.edu.my/6234/1/ONUBOGU_NNEKA_OBIANUJU.pdf http://eprints.utar.edu.my/6234/
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spelling	my-utar-eprints.62342024-03-11T14:02:44Z Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring Onubogu, Nneka Obianuju S Agriculture (General) TA Engineering (General). Civil engineering (General) Pipelines undergo deformation leading to leakage several times throughout their service life. Hence, there is a need for Structural Health Monitoring (SHM) to ensure the safety of pipelines. Various conventional SHM and fiber optics technology methods for pipeline leakage detection have been explored in the past, most of which are expensive; have slow response time; limited coverage, and limited sensitivity. This thesis presents a cost�effective and highly sensitive Erbium-doped fiber laser (EDFL) sensor that was designed and tested for its effectiveness in pipeline leakage and location detection. Results obtained showed an overall sensor accuracy of 90 % for leak location detection. However, during the tests, some instabilities were observed in the sensor. This led to the experimental and theoretical study of the behavior (including chaotic conditions) of the modulated EDFL to understand the cause of the instabilities. Two EDFL configurations (linear cavity – EDFLL and ring cavity – EDFRL) both under pump and external cavity-loss modulations were analyzed experimentally and theoretically. The bifurcation diagrams obtained showed resonance peaks, regions of chaos, and optical bi-stability confirming that the existence of bifurcation is the root cause of the EDFL's unstable behavior. For the theoretical analysis, a modified model built from two rate equations of a class B laser was presented. The model generates all spectral characteristics obtained during experimental pump and external cavity-loss modulations of the two EDFL configurations and can therefore be used to quickly predict the results of the EDFL sensor for further improvement in the future. It has been proven that the dynamic response of the pump-modulated EDFLL and EDFRL can be theoretically predicted with total average accuracies of: 91.09 % (EDFLL) and 86.60 % (EDFRL) in terms of the “resonance peaks”; and 91.58 % (EDFLL) and 90.79 % (EDFRL) in terms of the “frequency after which saturation occurred”. Similarly, it has been proven that the dynamic response of the cavity-loss modulated EDFLL and EDFRL can be theoretically predicted with total average accuracies of: 91.04 % (EDFLL) and 91.07 % (EDFRL) in terms of the “resonance peaks”; and 91.70 % (EDFLL) and 95.96 % (EDFRL) in terms of the “frequency after which saturation” occurred. The EDFLL and the EDFRL are highly sensitive to external perturbations such as acoustic waves even at low frequencies ranging from 100 Hz to 100 kHz and can be used for pipeline monitoring. 2023 Final Year Project / Dissertation / Thesis NonPeerReviewed application/pdf http://eprints.utar.edu.my/6234/1/ONUBOGU_NNEKA_OBIANUJU.pdf Onubogu, Nneka Obianuju (2023) Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring. PhD thesis, UTAR. http://eprints.utar.edu.my/6234/
institution	Universiti Tunku Abdul Rahman
building	UTAR Library
collection	Institutional Repository
continent	Asia
country	Malaysia
content_provider	Universiti Tunku Abdul Rahman
content_source	UTAR Institutional Repository
url_provider	http://eprints.utar.edu.my
topic	S Agriculture (General) TA Engineering (General). Civil engineering (General)
spellingShingle	S Agriculture (General) TA Engineering (General). Civil engineering (General) Onubogu, Nneka Obianuju Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
description	Pipelines undergo deformation leading to leakage several times throughout their service life. Hence, there is a need for Structural Health Monitoring (SHM) to ensure the safety of pipelines. Various conventional SHM and fiber optics technology methods for pipeline leakage detection have been explored in the past, most of which are expensive; have slow response time; limited coverage, and limited sensitivity. This thesis presents a cost�effective and highly sensitive Erbium-doped fiber laser (EDFL) sensor that was designed and tested for its effectiveness in pipeline leakage and location detection. Results obtained showed an overall sensor accuracy of 90 % for leak location detection. However, during the tests, some instabilities were observed in the sensor. This led to the experimental and theoretical study of the behavior (including chaotic conditions) of the modulated EDFL to understand the cause of the instabilities. Two EDFL configurations (linear cavity – EDFLL and ring cavity – EDFRL) both under pump and external cavity-loss modulations were analyzed experimentally and theoretically. The bifurcation diagrams obtained showed resonance peaks, regions of chaos, and optical bi-stability confirming that the existence of bifurcation is the root cause of the EDFL's unstable behavior. For the theoretical analysis, a modified model built from two rate equations of a class B laser was presented. The model generates all spectral characteristics obtained during experimental pump and external cavity-loss modulations of the two EDFL configurations and can therefore be used to quickly predict the results of the EDFL sensor for further improvement in the future. It has been proven that the dynamic response of the pump-modulated EDFLL and EDFRL can be theoretically predicted with total average accuracies of: 91.09 % (EDFLL) and 86.60 % (EDFRL) in terms of the “resonance peaks”; and 91.58 % (EDFLL) and 90.79 % (EDFRL) in terms of the “frequency after which saturation occurred”. Similarly, it has been proven that the dynamic response of the cavity-loss modulated EDFLL and EDFRL can be theoretically predicted with total average accuracies of: 91.04 % (EDFLL) and 91.07 % (EDFRL) in terms of the “resonance peaks”; and 91.70 % (EDFLL) and 95.96 % (EDFRL) in terms of the “frequency after which saturation” occurred. The EDFLL and the EDFRL are highly sensitive to external perturbations such as acoustic waves even at low frequencies ranging from 100 Hz to 100 kHz and can be used for pipeline monitoring.
format	Final Year Project / Dissertation / Thesis
author	Onubogu, Nneka Obianuju
author_facet	Onubogu, Nneka Obianuju
author_sort	Onubogu, Nneka Obianuju
title	Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
title_short	Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
title_full	Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
title_fullStr	Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
title_full_unstemmed	Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
title_sort	theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring
publishDate	2023
url	http://eprints.utar.edu.my/6234/1/ONUBOGU_NNEKA_OBIANUJU.pdf http://eprints.utar.edu.my/6234/
_version_	1794644943655927808
score	13.211869

Theoretical and experimental study of erbium-doped fiber laser chaotic conditions in response to acoustic vibrations for pipe leakage monitoring

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