The University of Southampton
University of Southampton Institutional Repository

Photosensitive and piezoelectric thin films for optical devices

Photosensitive and piezoelectric thin films for optical devices
Photosensitive and piezoelectric thin films for optical devices
This thesis reports on the development of photosensitive and piezoelectric thin films for optical devices. The thesis is in two parts, the first concentrating on research into novel photosensitive materials for optical Bragg gratings, while Part II studies the development of piezoelectric ZnO thin films for acousto-optic devices.

Bragg gratings are an important element in the development of optical communications systems. Strongly photosensitive optical waveguiding materials are required to achieve more efficient Bragg gratings in both planar and fibre waveguides. In this thesis, metal oxides are studied for photosensitivity in their pure state as RF sputtered thin films. Photosensitivity is demonstrated for the first time in RF sputtered germanium oxide and tantalum oxide thin film waveguides via Bragg diffraction. A side-polished fibre coupler, capable of monitoring both the magnitude and sign of an index change, is then used to establish large, negative and permanent index changes in tantalum oxide thin films. UV-induced changes in absorption, measured in a similar tantalum oxide film, are contrasted with the observed index change via a Kramers-Kronig analysis, while a UV-induced reduction in film reflectivity consolidates the fibre coupler result.

ZnO, with a kt of 0.28, is an efficient piezoelectric material, and thin ZnO transducers permit operating frequencies of up to 3.5 GHz. In addition, ZnO transducers can be configured on curved surfaces, whose focusing properties greatly enhance device efficiency. In contrast, the operating frequency of LiNbO3 transducers is limited to approximately 0.8 GHz and curved transducers are a problem. Part II of this thesis discusses the fabrication and optimisation of ZnO transducers. Acousto-optic beam deflection by ZnO transducers on TeO2 crystals is demonstrated for the first time, and efficient in-line fibre phase modulation is achieved using a annular ZnO transducer on an optical fibre.
Roe, Merrion Patricia
7d3dbe4c-bab7-4ecd-bb4f-2e85dd25705f
Roe, Merrion Patricia
7d3dbe4c-bab7-4ecd-bb4f-2e85dd25705f
Pannell, C.N.
002fadf4-f97e-4732-b171-73ed7563ee18
Hempstead, M.
1bc4f2eb-fba7-46b8-b0c6-199f586b9954

Roe, Merrion Patricia (1996) Photosensitive and piezoelectric thin films for optical devices. University of Southampton, Faculty of Engineering and Applied Science, Doctoral Thesis, 244pp.

Record type: Thesis (Doctoral)

Abstract

This thesis reports on the development of photosensitive and piezoelectric thin films for optical devices. The thesis is in two parts, the first concentrating on research into novel photosensitive materials for optical Bragg gratings, while Part II studies the development of piezoelectric ZnO thin films for acousto-optic devices.

Bragg gratings are an important element in the development of optical communications systems. Strongly photosensitive optical waveguiding materials are required to achieve more efficient Bragg gratings in both planar and fibre waveguides. In this thesis, metal oxides are studied for photosensitivity in their pure state as RF sputtered thin films. Photosensitivity is demonstrated for the first time in RF sputtered germanium oxide and tantalum oxide thin film waveguides via Bragg diffraction. A side-polished fibre coupler, capable of monitoring both the magnitude and sign of an index change, is then used to establish large, negative and permanent index changes in tantalum oxide thin films. UV-induced changes in absorption, measured in a similar tantalum oxide film, are contrasted with the observed index change via a Kramers-Kronig analysis, while a UV-induced reduction in film reflectivity consolidates the fibre coupler result.

ZnO, with a kt of 0.28, is an efficient piezoelectric material, and thin ZnO transducers permit operating frequencies of up to 3.5 GHz. In addition, ZnO transducers can be configured on curved surfaces, whose focusing properties greatly enhance device efficiency. In contrast, the operating frequency of LiNbO3 transducers is limited to approximately 0.8 GHz and curved transducers are a problem. Part II of this thesis discusses the fabrication and optimisation of ZnO transducers. Acousto-optic beam deflection by ZnO transducers on TeO2 crystals is demonstrated for the first time, and efficient in-line fibre phase modulation is achieved using a annular ZnO transducer on an optical fibre.

Text
Roe_1996_thesis_1030T - Author's Original
Restricted to Repository staff only
Available under License University of Southampton Thesis Licence.

More information

Published date: January 1996
Organisations: University of Southampton

Identifiers

Local EPrints ID: 398885
URI: http://eprints.soton.ac.uk/id/eprint/398885
PURE UUID: be453e0d-e5d4-4f10-8372-c7765d0f269a

Catalogue record

Date deposited: 15 Sep 2016 15:44
Last modified: 15 Mar 2024 01:44

Export record

Contributors

Author: Merrion Patricia Roe
Thesis advisor: C.N. Pannell
Thesis advisor: M. Hempstead

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×