Publications by Luc Thévenaz | EPFL Graph Search

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A method to measure the signal power evolution along phase-sensitive parametric amplifiers is proposed using Brillouin optical time-domain analysis. Different evolutions along the fiber are reported by varying input wave phases, including amplification and ...

Distributed optical fibre sensors possess the unique capability of measuring the spatial and temporal map of environmental quantities that can be of great interest for several field applications. Although existing methods for performance enhancement have e ...

In our work, we used stimulated Brillouin scattering directly in the gas medium (such as air) filling a hollow-core fiber to realize a massive optical amplification, by a factor of 200,000. ...

A novel configuration is presented here, based on the pump and probe technique, that has the following advantages: 1) few optical elements are required, 2) a single laser source is used, 3) a single fiber end is accessed, 4) only pulsed signals propagate.

We evaluate the Brillouin frequency shift (BFS) determination error when using the Brillouin phase spectrum (BPS) instead of the Brillouin gain spectrum (BGS) in BOTDA setups. We compare the error obtained in the BFS determination in both cases, both with ...

On-site distributed strain measurements using an original Brillouin analyser were performed on cables using standard tensile test bench and on critical installations in the Swiss telecom network.

We show that the spectral broadening of the pump pulse through self-phase modulation in a time-domain distributed Brillouin sensor has a considerably detrimental effect in the measurement, especially in the case of long distances and high-resolution pulses ...

Sub-ppm hydrogen chloride (HCl) and water vapour (H2O) monitoring using photoacoustic spectroscopy in optical fibre manufacturing is reported. The development and performance of a sensor based on an acoustic resonant configuration is described, and on-site ...

Energy transfer between the interacting waves in a distributed Brillouin sensor can result in a distorted measurement of the local Brillouin gain spectrum, leading to systematic error. We demonstrate here that this behavior can be fully and precisely model ...

Brillouin gain curves of a standard optical fibre have been measured down to 3 K. In comparison with their well-documented characteristics at room temperature, they show original and interesting features, namely non-monotonous variations of the central frequency shift and of the linewidth. These preliminary measurements indicate that Brillouin-based temperature sensors can advantageously be used in cryogenics with some adaptations.

Optical amplification in hollow core fibers has been achieved using stimulated Brillouin scattering directly in the gaseous medium. More than 50 dB optical gain is observed over 50 m of fiber using 200 mW of pump power. ...

Brillouin slow light in optical fibers is a promising technique for the development of all-optical buffers to be used in optical routers. The main drawback of this technique up to now has been its narrow bandwidth, normally restricted to 35 MHz in conventi ...

A novel method is proposed to measure the local birefringence in a standard fibre using the polarisation dependence of stimulated Brillouin scattering, in a non-destructive and simple way.

Brillouin time-domain analysis in optical fibres is a novel technique making possible a distributed measurement of temperature and strain over long distance and will deeply modify our view about monitoring large structures, such as dams, bridges, tunnels a ...

Image processing is proposed to enhance the performance of Brillouin distributed fibre sensors. The technique exploits the two-dimensional nature of the measurements, so that each frequency-position pair is assimilated to a pixel of a noisy image. Based on ...

Optical fibers have crucially contributed to promote the concept of distributed sensing with a large impact. The different types of fiber optics distributed sensing techniques are reviewed and their performances and limits are presented. ...

A closed-loop servo control based on balancing the gain of two probing frequencies is proposed for real-time Brillouin optical time-domain analysis (BOTDA) without post-processing. With the most basic BOTDA hardware setup, the system can perform measuremen ...

Slowing light is expected to enhance light-matter interaction, leading to more compact sensing devices. By simple tests we show that the reality is more complex and the only relevant quantity is the wave electric field. ...

Brillouin scattering in gas shows unmatched gain properties in hollow-core optical fibers filled at high pressure. Here, the gain characteristics are studied for two common gases, namely, N2 and CO2, which show distinct features and are compared to expecte ...

Luc Thévenaz

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Distributed Measurement of Signal Power Evolution in a Phase Sensitive Parametric Amplifier

Complete Broadening Compensation in a Slow Light System Using a Non-Linear Regeneration Element

Intensifying the response of distributed optical fibre sensors using 2D and 3D image restoration

Giant Brillouin Amplification in Gases

Simple distributed temperature sensor based on Brillouin gain spectrum analysis

Gain vs phase in BOTDA setups

Tensile tests on optical fibre cables using distributed Brillouin analysis

Detrimental effect of self-phase modulation on the performance of Brillouin distributed fiber sensors

Multi-hydrogenated compounds monitoring in optical fibre manufacturing process by photoacoustic spectroscopy

Depletion in a distributed Brillouin fiber sensor: practical limitation and strategy to avoid it

Brillouin gain curve measurements in fibres at cryogenic temperatures

Giant Brillouin Amplification in Gas Using Hollow-core Fiber

Arbitrary-bandwidth Brillouin slow light in optical fibers

Evaluation of local birefringence along fibres using Brillouin analysis

Fibre Distributed Sensing for a More Secure Society

Intensifying Brillouin distributed fibre sensors using image processing

Review and Progress on Distributed Fibre Sensing

Closed-loop technique based on gain balancing for real-time Brillouin optical time-domain analysis

Gas Sensing using Material and Structural Slow Light Systems

Study of backward Brillouin scattering in gas-filled anti-resonant fibers