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Luc Thévenaz

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Publications associées (373)

Closed-loop technique using gain balance for fast Brillouin Optical Time-Domain Analysis

Luc Thévenaz, Zhisheng Yang, Li Zhang, Ana Gabriela Correa Mena

A closed-loop servo control based on the gain ratio of two probing frequencies is proposed for fast BOTDA, where the feedback is independent of probe and pump loss, making it robust in harsh environment. ...

Optica Publishing Group2022

Distributed measurement of mode group effective refractive index difference in a few mode optical fibers

Luc Thévenaz, Zhisheng Yang, Alejandro Dominguez Lopez

The possibility to perform distributed measurements of the effective refractive index difference between distinct modes in few mode optical fibers is demonstrated using phase sensitive optical time domain reflectometry. Effective refractive index differenc ...

2022

Distributed Temperature Sensing Using Gas-filled Conjoined-tube Anti-resonant Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal

Distributed temperature measurement is conducted for the first time in a gas-filled conjoined-tube hollow-core anti-resonant fiber (HC-CAF) at a pressure of 34.7 bar. A Brillouin gain of 0.08 m−1W−1 and a temperature sensitivity of 2 MHz/K are yielded. ...

Optica Publishing Group2022

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

Luc Thévenaz, Zhisheng Yang, Li Zhang, Ana Gabriela Correa Mena

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 ...

2022

Distributed Fibre Optic Thermo-hygrometer for Monitoring the Concrete Curing

Luc Thévenaz, Kenny Hey Tow, Tiago Filipe Pimentel Das Neves

The moisture content in concrete is a critical parameter for most of the degradation processes such as shrinkage and cracking. In this paper, we present the first kilometre-range thermo-hygrometer for monitoring the concrete curing. ...

Optica Publishing Group2022

Numerical Studies of Brillouin-induced Polarization Pulling of Probe and Pump in Weakly-Birefringent Optical fibers with Applications to BOTDA

Luc Thévenaz, Marcelo Alfonso Soto Hernandez

Numerical solution of the involved governing equations confirm that the commonly used two orthogonal sets of gain- and loss-probes in BOTDA, differently affect the evolution of the pump state-of- polarization, thereby potentially compromising the minimizat ...

Optica Publishing Group2022

Enhanced Signal-Associated Noise in a φ-OTDR System

Luc Thévenaz, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

Owing to their high sensitivity with respect to external measurands, Rayleigh-based distributed optical fiber sensors (DOFS) find their way into applications in many industrial and academic sectors. To further transcend the limit of these sensors in terms ...

2022

High spatial resolution distributed and dynamic strain sensing using direct detection

Luc Thévenaz, Zhisheng Yang, Li Zhang

A distributed dynamic strain sensing system based on frequency-scanned phase-sensitive optical time domain reflectometry is proposed and demonstrated. It demonstrates a record spatial resolution of 20 cm, compared with other direct-detection dynamic strain ...

Optica Publishing Group2021

Waveguide and Gas: the Advent of a New Tool for Photonics

Luc Thévenaz, Flavien Gyger

The realisation of hollow-core fibres and nano-waveguides offers a unique opportunity to optimise the interactions between light and a gaseous medium. Stimulated Brillouin scattering is exploited to achieve unprecedented levels of amplification and to real ...

IEEE2021

On the Measurement Accuracy of Coherent Rayleigh-based Distributed Sensors

Luc Thévenaz, Simon Adrien Zaslawski, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

The phase change of back-scattered light due to external perturbations is retrieved in coherent Rayleigh-based distributed sensors by estimating the frequency shift (FS) between the traces of different measurements. The uncertainty associated with the esti ...

2021

Giant Brillouin Amplification in Gas Using Hollow-core Fiber

Luc Thévenaz, Flavien Gyger

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. ...

Optical Society of America2021

Determination of the Measurement Accuracy of a Phase-sensitive OTDR

Luc Thévenaz, Zhisheng Yang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

This paper presents the measurement accuracy of a phase-sensitive optical time-domain reflectometer (ϕ-OTDR) as a function of SNR and pulse width. A method to determine the absolute SNR of a ϕ-OTDR system is also proposed. ...

OSA2021

Impact of optical noises on unipolar-coded Brillouin optical time-domain analyzers

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Zhisheng Yang, Jian Wu, Sheng Wang

Noise models for both single-pulse and coded Brillouin optical time-domain analyzers (BOTDA) are established to quantify the actual signal-to-noise ratio (SNR) enhancement provided by pulse coding at any fiber position and in any operating condition. Simul ...

2021

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

Bertrand Dutoit, Luc Thévenaz, Bertrand Dutoit, Arooj Akbar, Zhisheng Yang, Nicolo' Riva

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 ...

IEEE Institute of Electrical and Electronics Engineers2021

Long-distance distributed pressure sensing based on frequency-scanned phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Zhisheng Yang, Li Zhang

In this paper, a long-distance distributed pressure sensing system based on a special fiber and using frequency-scanned phase-sensitive optical time-domain reflectometry is proposed. The fiber shows high pressure sensitivity (159 MHz/bar) and low loss (3 d ...

2021

Evaluating measurement uncertainty in Brillouin distributed optical fibre sensors using image denoising

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Simon Adrien Zaslawski, Zhisheng Yang

In 2016, our research team proposed in an issue of Nature Communications1 the use of multidimensional signal processing, especially image denoising techniques, to improve the signal-to-noise ratio (SNR) of distributed optical ﬁbre sensors. The beneﬁts of t ...

Nature Research2021

Distributed optomechanical fiber sensing based on serrodyne analysis

Luc Thévenaz, Simon Adrien Zaslawski, Zhisheng Yang

Distributed measurement of forward stimulated Brillouin scattering (FSBS) attracted substantial attention for its ability to probe media surrounding optical fibers. Currently, all techniques extract the information from the FSBS-induced local energy transf ...

2021

Distributed Temperature Sensing Based on φ-OTDR Using Back-reflection-enhanced Fiber

Luc Thévenaz, Li Zhang, Malak Mohamed Hossameldeen Omar Mohamed Galal, Suneetha Sebastian

Distributed temperature sensing with 10 dB back-reflection-enhanced fiber is performed based on φ-OTDR. While the temperature sensitivity of such fibers is similar to that of standard single-mode fibers, a 3-times higher temperature resolution is observed. ...

Optical Society of America2021

Distributed fiber temperature alarm system based on thermodynamic phase transition

Luc Thévenaz, Flavien Gyger, Li Zhang

A novel temperature sensing mechanism is proposed for the first time, based on thermodynamic phase transitions of CO2 in hollow-core fibers. A fast, sensitive and distributed fiber temperature alarm system is demonstrated using this concept. ...

Optica Publishing Group2020

Reaching mK-scale stability in CP-ɸOTDR over daily measurements

Luc Thévenaz, Tiago Filipe Pimentel Das Neves, Luis Costa

We propose several processing methods to mitigate the probability of large errors in Chirped-pulse ɸOTDR, improving performances for long-term measurements. For no perturbation applied, we reach a 2 mK error after a 24 h experiment. ...

2020

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