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, Sheng Wang, Jian Wu

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, Li Zhang, Zhisheng Yang

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, Malak Mohamed Hossameldeen Omar Mohamed Galal, Zhisheng Yang, 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

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

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

Zhisheng Yang, Arooj Akbar

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, Zhisheng Yang, Simon Adrien Zaslawski

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