Publications by Luc Thévenaz | EPFL Graph Search

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The polarization-related properties of stimulated Brillouin scattering (SBS) processes in long, randomly birefringent, standard optical fibers are examined. Evolution equations for the pump and signal waves, in the presence of both birefringence and SBS, are provided in Jones and Stokes spaces. It is shown that in the undepleted pump regime, the amplification of the SBS signal wave is equivalent to that of a linear medium with polarization-dependent gain. The process is associated with a pair of orthogonal

Elastic vibrations in subwavelength structures have gained importance recently in fundamental light–matter studies and various optoacoustic applications. Existing techniques have revealed the presence of distinct acoustic resonances inside silica microwire ...

A general analytic solution for Brillouin distributed sensing in optical fibers with sub-meter spatial resolution is obtained by solving the acoustical-optical coupled wave equations by a perturbation method. The Brillouin interaction of a triad of square ...

A theoretical description of photoacoustic spectroscopy generated by wavelength modulation of a semiconductor laser source is reported for a Lorentzian absorption line. This model describes the first- and second-harmonic photoacoustic signals produced by a ...

In this paper we describe and implement a long-range Brillouin optical time-domain analysis (BOTDA) sensor, for both temperature and strain measurements, using optical pulse coding techniques. A theoretical analysis of Simplex coding applied to BOTDA syste ...

A new and compact photoacoustic sensor for trace gas detection in the 2-2.5 μm atmospheric window is reported. Both the development of antimonide-based DFB lasers with singlemode emission in this spectral range and a novel design of photoacoustic cell adap ...

Development of standards and guidelines for performance specifications and testing for fibre optic sensors has been discussed since the mid-nineties of the last century in the scientific community as well as in the industry. Very global standards for the use of fibre optic components in data communication and telecommunication have been available for more than 20 years. Guidelines or substantial standards for fibre optic sensors are rather an exception. The first standard draft on generic specification of f

Dynamic reconfiguration of a microwave photonic filter by tuning its basic delay based on stimulated Brillouin scattering-induced slow light and optical phase shift of the optical carrier is experimentally implemented. The measurements confirm that the fre ...

The energy transfer between the two interacting optical waves in a distributed sensor based on stimulated Brillouin scattering can lead to a non-uniform spectral distribution of the pumping power after a long propagation. This results in a spectrally disto ...

Sinc-shaped Nyquist pulses possess a rectangular spectrum, enabling data to be encoded in a minimum spectral bandwidth and satisfying by essence the Nyquist criterion of zero inter-symbol interference (ISI). This property makes them very attractive for com ...

We have experimentally studied the effects of gamma-radiation up to very high total doses on the physical properties of Brillouin scattering in standard commercially available optical fibres. A frequency variation of about 5 MHz for both Brillouin frequenc ...

Instruments for distributed fiber-optic measurement of temperature are now available with temperature resolution of 0.01°C and spatial resolution of 1 m with temporal resolution of fractions of a minute along standard fiber-optic cables used for communicat ...

The health monitoring of superconducting fault current limiters (SFCL) is important for their large-scale exploitation in HVDC grids protection. The intrinsic non-homogeneity of critical current along the superconductor length can cause localized points of ...

Sinc-shaped Nyquist-pulses possess a rectangular spectrum. Thus, a sinc-pulse transmission minimizes the carrier spacing down to the baud rate, and therefore, substantially increases the transmissible data rates. These perspectives have led to a strong res ...

This invention relates to a system and method to determine the distributed birefringence profile along an optical fibre. Birefringence manifests as different refractive indices for two orthogonal states of polarization of the light propagating in the optic ...

Photonic Crystal Fibers (PCF) play a crucial role for fundamental investigations such as acousto-optical interactions as well as for applications, such as distributed sensors. One limiting factor for these experiments is the fiber inhomogeneity owing to th ...

Optical fibres offer the possibility to realize distributed sensing, which means that each point along the fibre can separately and selectively sense quantities such as temperature, strain, acoustics, and pressure, in total similarity to a real organic nerve. The fibre can therefore distinctively inform on the position of the stimulus and on its magnitude. This unique feature makes the optical fibre actually play two essential roles: linear sensing element transducing the quantity value into an optical modu

We provide a complete experimental characterization of stimulated Brillouin scattering in a 160 m long solid-core photonic crystal fiber, including threshold and spectrum measurements as well as positionresolved mapping of the Brillouin frequency shift. In ...

The experimental validation of a numerical technique for temperature/strain profile reconstruction based on Brillouin optical-fibre time-domain analysis (BOTDA) sensors is presented. In this approach, we search directly for the Brillouin frequency shift pr ...

Inelastic scatterings turn out to occupy an essential place in sensing applications, since they simply require a plain optical fibre as sensing element, with no special preparation. They give rise to energy and momentum transfers with the fibre material and make thus possible to access to material properties other than the simple optical linear response. In addition, inelastic scatterings can exist in a stimulated flavour that gives rise to dynamic couplings between all the waves involved in the interaction

Luc Thévenaz

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Polarization attributes of stimulated Brillouin scattering slow light in fiber

Local activation of surface and hybrid acoustic waves in optical microwires

Distributed Brillouin sensing with sub-meter spatial resolution: modeling and processing

Wavelength modulation photoacoustic spectroscopy: Theoretical description and experimental results

Long-range Brillouin optical time-domain analysis sensor employing pulse coding techniques

Novel Helmholtz-based photoacoustic sensor for trace gas detection at ppm level using GaInAsSb/GaAlAsSb DFB lasers

Guideline for Use of Fibre Optic Sensors

Dynamic Microwave Photonic Filter Using Separate Carrier Tuning Based on Stimulated Brillouin Scattering in Fibers

Impact of pump depletion on the determination of the Brillouin gain frequency in distributed fiber sensors

Optical sinc-shaped Nyquist pulses of exceptional quality

The effects of gamma-radiation on the properties of Brillouin scattering in standard Ge-doped optical fibres

Distributed fiber-optic temperature sensing for hydrologic systems

Optical fibre sensing for fast hotspot detection in SFCLs

Optical Nyquist-pulse generation with a power difference to the ideal sinc-shape sequence of < 1%

Method and apparatus for measuring the local birefingence along an optical waveguide

Effect of inhomogeneities on backward and forward Brillouin scattering in Photonic Crystal Fibers

State-Of-The-Art of Research on Distributed Optical Fibre Sensors

Complete experimental characterization of stimulated Brillouin scattering in photonic crystal fiber

A reconstruction technique for long-range stimulated Brillouin scattering distributed fibre-optic sensors: Experimental results

Inelastic Scatterings and Applications to Distributed Sensing