Publications by Luc Thévenaz | EPFL Graph Search

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An optical fibre sensing technique for the measurement of dynamic deformations using a Michelson interferometer is reported. The method applied to interferometers with an initial path unbalance of around 1 cm is based on the rf intensity modulation of a low-coherence source. A large measurement range of 1 cm is intrinsic to the method and with an adequate demodulation process sensitivity better than 10 μm is obtained. This novel approach allows for measuring dynamic deformations with a bandwidth up to 100 H

A novel kind of fiber-optic gyroscope based on Rayleigh backscattering in a fiber-ring resonator is presented in this letter. Information on the rotation rate is obtained from the composed response of the fiber ring to an optical time-domain reflectometry (OTDR) instrument. The developed model based on the coherence properties of the Rayleigh scattering yields a polarization-insensitive and low-cost gyroscope

A novel method for polarization dispersion measurements using an interferometric loop is presented. It can be achieved using a particularly simple setup and provides a representation of the probability distribution of the polarization dispersion.

The real remoteness of a distributed optical fiber sensor based on Brillouin optical time-domain analysis is considerably extended in this paper using seeded second-order Raman amplification and optical pulse coding. The presented analysis and the experime ...

Two new simple interferometric methods for birefringence measurements are described applying to either low- or high-birefringence fibres and to any kind of birefringence, the set-up being free of a polarizing device.

A novel demodulation technique for performing dynamic deformation measurements using a path-unbalanced Michelson interferometer is reported, The method is based on the rf amplitude modulation of a low-coherence source, and demodulation Is achieved by tracking in the frequency domain the position of the minimum of the detected intensity. This technique is particularly suitable for deformation measurements in civil engineering structures where deformations of the order of few millimeters over the sensor lengt

Based on the temperature change in an embankment, a seepage flow simulator and monitoring system based on distributed optical fiber sensing are proposed. A simulator is designed that consists of scale model of embankment with definite length, seepage flow ...

Rayleigh backscattering measurements on a fiber ring resonator enables to monitor loss and gyroscopic motion experienced by the ring. This easy-to-use technique yields to very sensitive fiber loss sensors and polarization-insensitive and low-cost gyroscopes.

Optical sensing offers an attractive solution to the societal concern for prevention of natural and human-generated threats and for efficient use of natural resources. The unprecedented properties of optical fibers make them ideal for implementing a ‘nervo ...

A system to interrogate photonic sensors based on long weak fiber Bragg gratings (FBGs) is presented and experimentally demonstrated, dedicated to measure the precise location of several spot events. The principle of operation is based on a technique used ...

We describe a new method for performing simultaneous position-resolved measurements of chromatic dispersion and Brillouin shift along single-mode optical fibers. The technique provides consistent high-resolution and low-noise results for both quantities. Our measurements indicate a certain correlation between both magnitudes, although the degree of correlation varies for the different manufacturers tested.

The distributed fibre sensing technology based on backward stimulated Brillouin scattering (BSBS) is experiencing a rapid development. However, all reported implementations of distributed Brillouin fibre sensors until today are restricted to detecting phys ...

A frequency-domain method is proposed to measure the inertial response of forward stimulated Brillouin scattering, so that the acoustic impedance of a liquid medium outside an uncoated 30 m standard single-mode fibre can be sensed. The proposed technique o ...

We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fibre. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scatteri ...

Standard multimode optical fibers normally support transmission over some 100 modes. Large differences in the propagation constant and the spatial distribution of distinct modes degrade the performance of phase-sensitive optical time-domain reflectometry m ...

This paper presents a thorough study of the different sources of noise affecting Brillouin optical time-domain analyzers (BOTDA), providing a deep insight into the understanding of the fundamental limitations of this kind of sensors. Analytical and experim ...

Generation of optical delays with minor amplitude change are realized through the superposition of gain and loss profiles generated by stimulated Brillouin scattering. It results in synthesized spectral profiles identical to an ideal electromagnetically-in ...

In a linear slow light system the delaying process is necessarily inducing distortion for fundamental reasons, strictly bounding the maximum delay-bandwidth product to unity. Slowing the light does not directly enhance light-matter interaction, but is a co ...

We experimentally verify the possibility of measuring the difference in effective refractive index between higher-order-modes using a phase-sensitive OTDR, indicating that it is possible to measure the average difference over long fiber spans.

Luc Thévenaz

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An optical fibre sensor for dynamic deformation measurements based on the intensity modulation of a low-coherence source

Rayleigh fiber optics gyroscope

Interferometric loop method for polarization dispersion measurements

Extending the Real Remoteness of Long-Range Brillouin Optical Time-Domain Fiber Analyzers

Birefringence characterization of fibres without polarizer

Measurement of dynamic deformations using a path unbalance Michelson interferometer based optical fiber sensing device

Design of simulator for seepage detection in an embankment based on distributed optic fibre sensing technology

Loss and gyroscopic sensing using Rayleigh scattering in a fiber ring resonator

Random-access distributed fiber sensing

Microwave photonics filtering technique for interrogating long weak fiber Bragg grating sensors

Simultaneous position-resolved mapping of chromatic dispersion and Brillouin shift along single-mode optical fibers

Distributed forward Brillouin sensor based on local light phase recovery

Frequency-domain technique to measure the inertial response of forward stimulated Brillouin scattering for acoustic impedance sensing

Light controlling light in an optical fibre: from very slow to faster-than-light speed

Frequency scanned phase sensitive optical time-domain reflectometry interrogation in multimode optical fibers

Sources of noise in Brillouin optical time-domain analyzers

Polarization Dependent Pulse Distortion in Stimulated Brillouin Scattering Slow Light Systems

Zero-Gain Slow Light in Optical Fibres

Fundamental aspects of linear slow light systems

Intermodal measurements in few-mode fibers with phase- sensitive OTDR