- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- Fibre optic sensors based on D-shaped elliptical core...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
Fibre optic sensors based on D-shaped elliptical core fibres Chandani, Sameer M.
Abstract
Optical fibre-based sensors have gained much attention over the past three decades and are gaining acceptance in many industries such as the aerospace, automotive, chemical processing, biological sensing, and medical industries. The work presented here demonstrates the use of D-shaped fibres as intensity-based fibre optic sensors. The fibres are etched to gain access to their evanescent optical fields and are operated in their "leaky", regimes, i.e., the regime in which optical power leaks out of their cores. The optical power transmission through the etched D-fibre, which constitutes the sensor head, depends on the refractive index of the measurand placed on the sensor head. Thus by using materials whose refractive indices depend on the desired measurands, intensity-based sensors can be realised. A "non-destructive" process for determining the etched cladding thickness of the D-fibre is also developed. Once calibrated for a specific fibre or fibre batch, only one thermo-optic oil, three temperature measurements and a mathematical fitting routine are required to determine the etched cladding thickness with an accuracy better than 0.3 μm. Four types of sensor are demonstrated. A refractive index sensor with a high resolution region and a low resolution region, both of which can be shifted by changing the operating wavelength, is demonstrated with a maximum resolution on the order of 10⁻⁶ refractive index units. Naturally, this leads to the development of a temperature sensor with an adjustable dynamic range and resolution that uses thermo-optic oils. Proof of principle is demonstrated for an electric field sensor using chiral smectic A liquid crystals. A continuous liquid level sensor (that can also be implemented as a discrete level sensor) is also demonstrated using only one optical source, one optical detector and a single length of fibre.
Item Metadata
Title |
Fibre optic sensors based on D-shaped elliptical core fibres
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
2007
|
Description |
Optical fibre-based sensors have gained much attention over the past three decades and are gaining acceptance in many industries such as the aerospace, automotive, chemical processing, biological sensing, and medical industries. The work presented here demonstrates the use of D-shaped fibres as intensity-based fibre optic sensors. The fibres are etched to gain access to their evanescent optical fields and are operated in their "leaky", regimes, i.e., the regime in which optical power leaks out of their cores. The optical power transmission through the etched D-fibre, which constitutes the sensor head, depends on the refractive index of the measurand placed on the sensor head. Thus by using materials whose refractive indices depend on the desired measurands, intensity-based sensors can be realised. A "non-destructive" process for determining the etched cladding thickness of the D-fibre is also developed. Once calibrated for a specific fibre or fibre batch, only one thermo-optic oil, three temperature measurements and a mathematical fitting routine are required to determine the etched cladding thickness with an accuracy better than 0.3 μm. Four types of sensor are demonstrated. A refractive index sensor with a high resolution region and a low resolution region, both of which can be shifted by changing the operating wavelength, is demonstrated with a maximum resolution on the order of 10⁻⁶ refractive index units. Naturally, this leads to the development of a temperature sensor with an adjustable dynamic range and resolution that uses thermo-optic oils. Proof of principle is demonstrated for an electric field sensor using chiral smectic A liquid crystals. A continuous liquid level sensor (that can also be implemented as a discrete level sensor) is also demonstrated using only one optical source, one optical detector and a single length of fibre.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2011-02-14
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0100612
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.