Publications by Zhisheng Yang | EPFL Graph Search

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A Brillouin optical time-domain analysis (BOTDA) method based on a closed-loop control system is proposed to track fast variations of the Brillouin frequency shift along the sensing fiber. Whilst the method eliminates the gain spectral scanning, the exact ...

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 ...

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 ...

The performance of unipolar unicolor coded Brillouin optical time-domain analysis (BOTDA) is evaluated based on both Simplex and Golay codes. Four major detrimental factors that limit the system performance, including decoded-gain trace distortion, coding ...

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 ...

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 ...

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 ...

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 ...

Aiming at taking full advantage of bipolar codes, a method using a three-tone probe is proposed to alleviate the probe power limitation imposed by pump depletion in Golay-coded Brillouin distributed fiber sensors. Experimental results validate the techniqu ...

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 ...

A novel technique is proposed to obtain a flexible and variable spatial resolution from a conventional Brillouin optical time-domain analyzers using a fast post-processing algorithm. The approach is very attractive since a fine spatial resolution can be ob ...

The distributed fibre sensing technology based on backward stimulated Brillouin scattering (BSBS) is experiencing a rapid development. However, all reported implementations of distributed Brillouin fibre sensors until today are restricted to detecting phys ...

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 ...

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 ...

Non-local effects have been traditionally identified as one of the most limiting factors of the performance of Brillouin optical time-domain analyzers. These phenomena, directly linked with the energy gained/lost by the pump pulse, limit the probe power an ...

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 ...

The signal-to-noise ratio (SNR) of the measurement for direct-detection Brillouin optical time-domain analyzers is modelled and experimentally validated, with and without the use of optical pre-amplification. Results indicate that preamplification associat ...

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 ...

Commonly, the frequency shift of back-reflection spectra is the key parameter to measure quantitatively local temperature or strain changes in frequency-scanned Rayleigh-based distributed fiber sensors. Cross-correlation is the most common method to estima ...

Zhisheng Yang

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Brillouin Distributed Optical Fiber Sensor Based on a Closed-Loop Configuration

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

Optical fibre sensing for fast hotspot detection in SFCLs

Design rules for optimizing unipolar coded Brillouin optical time-domain analyzers

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

Genetic-optimised aperiodic code for distributed optical fibre sensors

Novel scanning method for distortion-free BOTDA measurements

Short spatial resolutions retrieval from a long pulse BOTDA trace

Hotspot monitoring system for superconducting device

200 km fiber-loop Brillouin distributed fiber sensor using bipolar Golay codes and a three-tone probe

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

Short spatial resolutions retrieval from a long pulse BOTDA trace

Distributed forward Brillouin sensor based on local light phase recovery

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

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

Reaching the ultimate performance limit given by non-local effects in BOTDA sensors

Distributed optomechanical fiber sensing based on serrodyne analysis

Optimizing the signal-to-noise ratio for direct-detection BOTDA

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

Analysis and Reduction of Large Errors in Rayleigh-based Distributed Sensor