Développement d'un interféromètre extrinsèque à double cavités de type Fabry- Perot: Applications à la mesure de vibrations périodiques et non périodiques

Thomas Victor Rapporteur

Description

Niveau: Supérieur, Doctorat, Bac+8
THÈSE En vue de l'obtention du DOCTORAT DE L'UNIVERSITÉ DE TOULOUSE Délivré par Institut National Polytechnique de Toulouse Discipline ou spécialité : Microonde, ElectroMagnétisme et Optoélectronique JURY Prof. GOURINAT Yves Président Prof. GRATTAN Kenneth Thomas Victor Rapporteur Prof. BOISROBERT Christian Rapporteur Prof. MOLLIER Jean-Claude Examinateur Prof. CATTOEN Michel Examinateur Dr. PLANTIER Guy Examinateur Dr. FERDINAND Pierre Examinateur Dr. SEAT Han Cheng Directeur de thèse Présentée et soutenue par Saroj PULLTEAP Le 11.12.2008 Titre : Développement d'un interféromètre extrinsèque à double cavités de type Fabry- Perot: Applications à la mesure de vibrations périodiques et non périodiques Ecole doctorale : GEET Unité de recherche : LOSE Directeur(s) de Thèse : Dr. SEAT Han Cheng Rapporteurs : Prof. GRATTAN Kenneth Thomas Victor Prof. BOISROBERT Christian i

• cavity effpi


• fabry-perot device


• fiber optic


• sensing cavity


• demodulation scheme


• quadrature phase-shifted


• technique part


• phase-tracking demodulation

Sujets

• Rapporteur
• Institut national polytechnique de Toulouse
• Université de Toulouse
• Victor
• Ferdinand
• Fabry?Pérot interferometer
• Optical fiber

Informations

• Publié par: profil-zyak-2012
• Nombre de lectures: 23
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

THÈSE


En vue de l'obtention du

DOCTORAT DE L’UNIVERSITÉ DE TOULOUSE

Délivré par Institut National Polytechnique de Toulouse
Discipline ou spécialité : Microonde, ElectroMagnétisme et Optoélectronique


Présentée et soutenue par Saroj PULLTEAP
Le 11.12.2008

Titre : Développement d’un interféromètre extrinsèque à double cavités de type Fabry-
Perot: Applications à la mesure de vibrations périodiques et non périodiques



JURY
Prof. GOURINAT Yves Président
Prof. GRATTAN Kenneth Thomas Victor Rapporteur
Prof. BOISROBERT Christian Rapporteur
Prof. MOLLIER Jean-Claude Examinateur
Prof. CATTOEN Michel
Dr. PLANTIER Guy
Dr. FERDINAND Pierre Examinateur
Dr. SEAT Han Cheng Directeur de thèse


Ecole doctorale : GEET
Unité de recherche : LOSE
Directeur(s) de Thèse : Dr. SEAT Han Cheng
Rapporteurs : Prof. GRATTAN Kenneth Thomas Victor
Prof. BOISROBERT Christian


i































Acknowledgements
I would first like to thank Professor T. Bosch for giving me the opportunity to do my
research at the Laboratory Optoelectronic and Embedded systems (LOSE), ENSEEIHT, INP-
Toulouse, France. Moreover, I would also thank Dr. H. C. Seat, my thesis director, for his
continuous guidance, support, patience and encouragement throughout my PhD program. He
has always helped me through several difficult problems of the research and always suggested
to me ideas concerning the technical aspects of work. He showed me different ways to
approach a research problem and the need to be persistent to accomplish any goal. I have
gained much in terms of knowledge and experience in experimental research while working
with him. Not only scientific works, but he also taught me to broaden my vision when living
(studying, culture, and community) in foreign countries. Without his support, patience and
guidance, this research would not have been complete. Also, his openness and willingness
motivated me to execute and finish my thesis. Thank you.
I would also like to thank Professor M. Cattoen for his suggestion in phase-tracking
demodulation technique part. Without his suggestion, the non-periodic measurements would
not be measured.
I would also like to express my thanks for Prof. K.T.V. Grattan and Prof. Boisrobert
for reviewing my thesis and also thanks to Prof. Mollier, Prof. Gourinat and Dr. Ferdinand for
participating in my viva and giving me for future work.
I would also like to express my deepest gratitude to people who work in LOSE (Nicole,
Emmanuelle, Brigitte, Francoise, Julien, Francis, and Clement) for administration help and
technical support, and also my colleagues (Olivier, Caroline, Joseph, Maha, Usman, Laurent,
and Ahmad) for their friendship and help.
Due acknowledgement is also given to the Royal Thai Government for the financial
support in the form of a PhD scholarship. Without whose grant, this thesis would not have
been realized.

iii































Development of an Extrinsic dual-cavity Fiber Fabry-Perot
interferometer: Applications to periodic and non-periodic
vibration measurements
Abstract
The work involved in this thesis principally concerns the development and
characterization of a dual-cavity Extrinsic Fiber Fabry-Perot Interferometer (EFFPI), with the
specific aims of analyzing both periodic and non-periodic vibrations. This thesis is divided
into five chapters.
In chapter I, we provide a brief overview of vibration measurements and their
associated techniques, both optical and non-optical. A general description of the
characteristics of fiber optic interferometers most suited for this application is next included.
The emphasis on non-contact measurement, geometrical flexibility, accessibility to the
mesurand in question and the ease of deployment orientates our choice towards the fiber
Fabry-Perot device.
Chapter II presents the operating principles of the EFFPI. The device contains a
“virtual” pseudo-dual-cavity which is generated due to the introduction of polarization-
controlling optics into the optical path of the sensing cavity. This configuration enables two
sets of “quadrature phase-shifted” interference signals to be obtained, hence eliminating the
problem of directional ambiguity. The general properties of the interferometer, such as its
reflectance and fringe visibility, have been characterized. More importantly, the polarization
states of the injected and output lightwaves have been studied to further understand
polarization-induced signal attenuation with the aim of reducing this parasitic effect.
A modified zero-crossing fringe demodulation technique is described in chapter III for
processing the interference signals from the dual-cavity EFFPI sensor into useful
displacement information. The resolution of the demodulation scheme is determined by the
number of sub-levels into which the interference fringes can be divided. In this work, a λ/64
resolution is deemed sufficient for application in periodic vibrations with relatively large
amplitudes. Various signal types, such as sinusoidal, square, and triangular excitations have
been applied and experimentally verified. Possible errors due to temperature variation of the
laser source as well as the target orientation during displacement measurements are also
investigated.
vIn chapter IV, a phase-tracking technique is described for demodulating the
interference signals into the required/desired displacement of a target subjected to non-
periodic vibration. The development of a simulation and demodulation program enables the
analysis of out-of-quadrature phase errors, random noise effects, quantization noise, etc. The
detected phase errors can subsequently be corrected by the demodulator while the noise can
be reduced via an amplitude correction method. Experimental tests under squarewave
excitation carried out with a PieZo-electric Transducer (PZT) incorporating a capacitive
sensor demonstrated excellent agreement (difference of only a few nanometers). The EFFPI
sensor is next employed for two specific applications. In seismometry, the possibility of our
sensor for detecting both vibration amplitudes and velocities is aptly demonstrated. In
addition, the fiber sensor is also shown to be relatively accurate in measuring liquid level
variation in an optical inclinometry set-up based on two communicating short-base vases.
The final chapter concludes the work carried out in this thesis and proposes
perspectives for further enhancing the performance of the developed sensor.

Keywords: dual optical cavity, Fabry-Perot interferometer, quadrature, polarization states,
periodic and non-periodic vibrations, zero-crossing demodulation, phase-tracking
demodulation, seismometry, inclinometry.

viDéveloppement d’un interféromètre extrinsèque à double
cavités de type Fabry-Perot: Applications à la mesure de
vibrations périodiques et non périodiques

Résumé
Le travail présenté dans cette thèse concerne le développement et la caractérisation
d’un interféromètre extrinsèque à double cavités de type Fabry-Perot (EFFPI) en vue de
l’analyse de vibrations périodiques et non périodiques. Cette thèse est divisée en 5 chapitres.
Dans le chapitre I, nous donnons un panorama des mesures de vibration et de leurs
techniques associées de type optique ou non-optique. Nous fournissons une description
générale des caractéristiques des interféromètres à fibre optique. Nous justifions le choix du
système de type Fabry-Perot par ses propriétés de mesure sans contact, sa flexibilité
géométrique, ainsi que sa facilité d’utilisation.
Le chapitre II présente le principe de fonctionnement du EFFPI. Le système comprend
une cavité virtuelle pseudo-duale obtenue par l’introduction d’une optique de polarisation
dans le chemin optique de la cavité de mesure. Cette configuration permet d’obtenir deux
signaux d’interférence en quadrature, ce qui élimine l’ambiguïté de direction. Les propriétés
générales de l’interféromètre telles que la réflectance et la visibilité de franges ont été
caractérisées expérimentalement. En particulier, les états de polarisation des faisceaux
d’entrée et de sortie ont été étudié