Publications by Luc Thévenaz | EPFL Graph Search

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The spectral properties of the Rayleigh backscattered traces measured by a phase-sensitive optical time-domain reflectometer (øOTDR) with direct detection are theoretically and experimentally analyzed. The spectrum of the measured øOTDR signal is found to ...

Silicon nitride (Si3N4) has emerged as a promising material for integrated nonlinear photonics and has been used for broadband soliton microcombs and low-pulse-energy supercontinuum generation. Therefore, understanding all nonlinear optical properties of S ...

In a recent paper by Kovalev et al [Optics Express 17, 17317 (2009)] the coupled equations describing stimulated Brillouin scattering (SBS) were solved in the Fourier domain. The main conclusion driven by the authors was that SBS pump spectral broadening w ...

A novel BOTDA technique for distributed sensing of the Brillouin frequency in optical fibers with cm-order spatial resolution is proposed. The technique is based upon a simple modulation scheme, requiring only a single long pump pulse for acoustic excitati ...

Stimulated Brillouin scattering (SBS) amplification of probe signals is highly polarization dependent. Maximum and minimum gain values are associated with a pair of orthogonal states of polarization (SOP) at the fiber output. Since the maximum gain is much ...

Slow light systems are particularly attractive for analog signal processing, since their inherent limitation to a delay-bandwidth product of 1 is less critical for analog systems such as those used in microwave photonics. We present here the implementation of two basic functions - phase shifting and true time delaying - fully optically controlled using stimulated Brillouin scattering in optical fibers. The combination of these two functions makes possible the implementation of true time delays without limit

A simplified model describing the polarisation characteristics of spun fibres is proposed, aiming at determining how close to a circularly birefringent medium such a fibre is. This is of crucial importance regarding the interest of such a medium for magnet ...

In this paper a technique to measure the distributed birefringence profile along optical fibers is proposed and experimentally validated. The method is based on the spectral correlation between two sets of orthogonally-polarized measurements acquired using ...

We experimentally demonstrate that all-optical signal calculus can be realized based on dynamic Brillouin gratings in optical fibers. Temporal integration and first-order differentiation were performed for optical pulse with various waveforms. ...

Continuously tunable, optically-controlled variable delay line based on dynamic Brillouin grating is exploited for automated synchronization of switching signals in a network node, enabling asynchronous contention resolution with packet priorization. ...

Multi-hydrogenated compounds detection based on photoacoustic (PA) spectroscopy is reported. Three near-infrared semiconductor lasers are used with a resonant PA cell operated in its first longitudinal mode to monitor methane, water vapour and hydrogen chloride in the parts per million range. The design of our cell results from simulations performed in order to optimise its performances. Influence of the buffer gas on the PA signal has also been analysed, both theoretically and experimentally. A reduction o

A novel measurement scheme is presented for injection locking experiments with semiconductor lasers. In the method, the light generated by the master laser travels through an optical fiber before being injected into the cavity of the slave laser. Using the reciprocity principle, it is possible to control accurately the absolute light power injected from the master laser in the cavity of the slave laser once the power coupling coefficient between the slave waveguide mode and the fiber mode is determined. In

Superconducting fault current limiters (SFCLs) can be used to limit fault currents in both meshed DC and AC grids by transitioning from superconducting to resistive state, in the presence of high currents. While the device is theoretically a great way to p ...

A method for distributed birefringence measurements is proposed based on the interference pattern generated by the interrogation of a dynamic Brillouin grating (DBG) using two short consecutive optical pulses. Compared to existing DBG interrogation techniq ...

From the spider’s perspective, silk is not only a building material but also a safety net, a weapon and a sensory organ to detect the presence of prey on its web. For scientists, dragline silk - directly extracted from spiders - is a tough, biodegradable a ...

An ammonia traces analyser based on photoacoustic spectroscopy is described. The system uses a CO2 laser and a properly designed resonant photoacoustic cell to achieve ammonia detection at sub-parts-per- billion (ppb) level. The instrument features unattended automatic on-line monitoring of ammonia with a detection limit of 0.1 ppb. Interferences from atmospheric CO2 and H2O are efficiently suppressed by a careful selection of the laser wavelength and a compensation of the water vapour signal made with a hi

Distributed optical fibre sensors deliver a map of a physical quantity along an optical fibre, providing a unique solution for health monitoring of targeted structures. Considerable developments over recent years have pushed conventional distributed sensor ...

Systematic errors induced by distortions in the pump pulse of conventional Brillouin distributed fiber sensors are thoroughly investigated. Experimental results, supported by a theoretical analysis, demonstrate that the two probe sidebands in standard Bril ...

Temperature and strain discrimination is experimentally demonstrated in an elliptical-core polarization-maintaining fiber by making use of Rayleigh-based distributed birefringence measurements and the frequency shift of the correlation peak obtained by sta ...

The spectral broadening of the pump pulse through self phase modulation in a time domain distributed Brillouin sensor is demonstrated to have a non-negligible detrimental effect, leading to a doubling of the effective gain linewidth after some 20 km in sta ...

Luc Thévenaz

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Spectral Properties of the Signal in Phase-Sensitive Optical Time-Domain Reflectometry with Direct Detection

Observation of Stimulated Brillouin Scattering in Silicon Nitride Integrated Waveguides

“Slow Light” in stimulated Brillouin scattering: on the influence of the spectral width of pump radiation on the group index: Comment

High spatial resolution distributed sensing in optical fibers by Brillouin gain-profile tracing

Polarization pulling based on stimulated Brillouin scattering in a dual-pump configuration

Slow light fiber systems in microwave photonics

Spun fibres: a quasi circularly birefringent medium

Distributed phase birefringence measurements based on polarization correlation in phase-sensitive optical time-domain reflectometers

All-optical calculus based on dynamic Brillouin grating reflectors in optical fibers

All-Optical Self-Synchronizing Scheme for Contention Resolution in Asynchronous Optical Packet Switched Networks Using Continuously Tunable Optical Delay Line

Multi-gas sensing based on photoacoustic spectroscopy using tunable laser diodes

Novel measurement scheme for injection locking experiments with semiconductor lasers

Fast Hotspot Detection in SFCLs by Exploiting Strain Response in Optical Fiber Sensing

Highly-sensitive distributed birefringence measurements based on a two-pulse interrogation of a dynamic Brillouin grating

From spider webs to a fibre-optic chemical sensor

Ammonia monitoring at trace level using photoacoustic spectroscopy in industrial and environmental applications

Genetic-optimised aperiodic code for distributed optical fibre sensors

Novel scanning method for distortion-free BOTDA measurements

Discrimination of temperature and strain by combined refractive index and birefringence measurements using coherent Rayleigh sensing

Impact of self phase modulation on the performance of Brillouin distributed fibre sensors