Publications de Zhisheng Yang | EPFL Graph Search

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

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

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

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

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

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

Hotspot monitoring system for superconducting device

Arooj Akbar, Zhisheng Yang

Hotspot monitoring system for superconducting devices including: - a superconductor; - a first optical waveguide attached to the superconductor for providing a first optical signal; - a second optical waveguide for providing a reference signal; and - inter ...

2021

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

Study on the signal-to-noise ratio of Brillouin optical-time domain analyzers

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

The signal-to-noise ratio (SNR) of Brillouin optical time-domain analyzers (BOTDA) is modelled and experimentally validated, using direct detection with and without the use of optical pre-amplification. The behavior of SNR as a function of the Brillouin ga ...

2020

Opto-mechanical cross-talk reduction in air-holes multicore fibers

Luc Thévenaz, Simon Adrien Zaslawski, Zhisheng Yang, Yun Fu

We report on the use of air-holes in multicore fibers to alleviate intercore perturbations induced by forward stimulated Brillouin scattering. Comparisons with conventional multicore fibers show significant improvement in terms of cross-talk reduction. ...

Optical Society of America2020

Genetic-optimised aperiodic code for distributed optical fibre sensors

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

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 ...

Nature Research2020

Distributed and dynamic strain sensing with high spatial resolution and large measurable strain range

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

A distributed and dynamic strain sensing system based on frequency-scanning phase-sensitive optical time domain reflectometry is proposed and demonstrated. By utilizing an RF pulse scheme with a fast arbitrary waveform generator, a train of optical pulses ...

2020

Short spatial resolutions retrieval from a long pulse BOTDA trace

Luc Thévenaz, Simon Adrien Zaslawski, Zhisheng Yang, Sheng Wang

A novel, to the best of our knowledge, postprocessing technique is proposed to extract with a flexible and variable spatial resolution the information from Brillouin optical time-domain analyzers, obtained using a pulse longer than the acoustic settling ti ...

2020

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

Luc Thévenaz, Zhisheng Yang, Alejandro Dominguez Lopez

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 ...

AIP2020

On the 2D Post-Processing of Brillouin Optical Time-Domain Analysis

Luc Thévenaz, Simon Adrien Zaslawski, Zhisheng Yang

The benefits and limitations inherent to the 2D post-processing of measurements from Brillouin optical time-domain analyzers are investigated from a fundamental point of view. In a preliminary step, the impact of curve fitting on the precision of the estim ...

IEEE Institute of Electrical and Electronics Engineers2020

Optical fibre sensing for fast hotspot detection in SFCLs

Bertrand Dutoit, Luc Thévenaz, Bertrand Dutoit, Arooj Akbar, Zhisheng Yang, Sheng Wang

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 ...

2020

Performance analysis of the differential pulse-width pair Brillouin optical time domain analysis using the log normalized and linearly normalized gain

Luc Thévenaz, Simon Adrien Zaslawski, Zhisheng Yang

The performance of the differential pulse-width pair Brillouin optical time domain analysis (DPP-BOTDA) is evaluated experimentally using either the gain from log normalization or linear normalization for the subtraction of traces collected with pump pulse ...

SPIE2019