Publications de Xin Lu | EPFL Graph Search

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

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu, Li Zhang

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 ...

IEEE Institute of Electrical and Electronics Engineers2020

Impact of the fiber coating on the temperature response of distributed optical fiber sensors at cryogenic ranges

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

The thermomechanical behavior of a standard single mode fiber with different coating materials is theoretically analyzed under different temperature conditions. Results show that the thermal expansion/shrinkage of the fiber coating introduces an extra stra ...

IEEE Institute of Electrical and Electronics Engineers2018

Probabilistic Prediction and Forecast of Daily Suspended Sediment Concentration on the Upper Yangtze River

Mário Jorge Rodrigues Pereira Da Franca, José Pedro Gamito de Saldanha Calado Matos, Xin Lu

Sediment transport in suspension can represent more than 90% of a river's total annual flux of sediment. In the case of the Yangtze River, more than 99% of the sediment supplied to the sea is suspended load. Suspended sediment is thus an important componen ...

AMER GEOPHYSICAL UNION2018

Temperature-strain discrimination in distributed optical fiber sensing using phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

A method based on coherent Rayleigh scattering distinctly evaluating temperature and strain is proposed and experimentally demonstrated for distributed optical fiber sensing. Combining conventional phase-sensitive optical time-domain domain reflectometry ( ...

Optical Society of America2017

Temperature sensitivity enhancement in a standard optical fiber with double coatings at low temperature

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

The thermomechanical behavior of a standard optical fiber with double coating is theoretically analyzed at room temperature and ~ 220 K. As the primary coating becomes stiffer at low temperature, the impact of the thermal expansion of the coatings is no lo ...

Ieee2017

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

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

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 ...

SPIE2017

Method and apparatus for measuring the local birefingence along an optical waveguide

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

This invention relates to a system and method to determine the distributed birefringence profile along an optical fibre. Birefringence manifests as different refractive indices for two orthogonal states of polarization of the light propagating in the optic ...

2016

Coherent Rayleigh time domain reflectometry : novel applications for optical fibre sensing

Xin Lu

Owing to the advantages of the optical fibre, such as lightweight, small size, low cost and immunity to electromagnetic interferences, the fibre sensors have been applied in diverse fields and the scientific research on fibre sensing keeps improving to mee ...

EPFL2016

Characterisation of an electrical heating method for metallic-coated optical fibres for distributed sensing applications

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

In several applications a temperature contrast between the sensing fibre and the environment is required to detect changes in the environmental heat capacity. For this purpose the process of electrical heating in metallic-coated fibres is theoretically ana ...

Spie-Int Soc Optical Engineering2016

Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order o ...

Spie-Int Soc Optical Engineering2016

Optimal detection bandwidth for phase-sensitive optical time-domain reflectometry

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

The spectrum of the temporal traces obtained from a phase-sensitive optical time-domain reflectometer is theoretically and experimentally analysed, demonstrating its dependence on the incident optical pulse shape. Numerical simulations and theoretical resu ...

Spie-Int Soc Optical Engineering2016

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

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

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 ...

Optical Society of America2015

MilliKelvin resolution in cryogenic temperature distributed fibre sensing based on coherent Rayleigh scattering

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

The response of a distributed temperature sensor based on coherent Rayleigh scattering is experimentally studied in the temperature range from 77 K up to 300 K, using fibres with standard and ORMOCER coating. A precise and absolute frequency scan is perfor ...

SPIE2014

Brillouin distributed fibre sensing using phase modulated probe

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Xin Lu

A novel configuration for a Brillouin distributed sensor using a phase modulated probe is presented. It offers the combined advantages of a direct implementation using simple devices and a large immunity to noise, shifting the information from the baseband ...

Spie-Int Soc Optical Engineering2013