Publications de Kenny Hey Tow | EPFL Graph Search

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

Fiber Bragg grating-based thermometer for drill bit temperature monitoring

Luc Thévenaz, Kenny Hey Tow

The temperature measurement of a drill bit during an implantology drilling process is proposed by using a fiber Bragg grating fitted inside the drill bit. Due to the rotational nature of the drilling process, a free-space fiber-optic rotary joint is used f ...

2019

A kilometre-range distributed relative humidity sensor

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

Fibre optics sensors have been identified as very good candidates for environmental monitoring inside the silicon detectors operated at CERN’s Large Hadron Collider. In this study, we present the results from the first highly sensitive relative humidity di ...

SPIE2019

High Signal-to-Noise Ratio Stimulated Brillouin Scattering Gain Spectrum Measurement

Luc Thévenaz, Flavien Gyger, Marcelo Alfonso Soto Hernandez, Kenny Hey Tow, Zhisheng Yang

A technique to measure nonlinear processes, such as stimulated Brillouin scattering, with a very-high signal-to-noise ratio (SNR) is presented. Brillouin gain measurement with 77dB SNR is demonstrated over a 2m-long section of single-mode fiber. ...

Optical Society of America2018

Distributed hydrostatic pressure measurement using phase-OTDR in a highly birefringent photonic crystal fibre

Luc Thévenaz, Kenny Hey Tow, Li Zhang

We demonstrate a distributed hydrostatic pressure measurement based on phase-sensitive optical time-domain reflectometry in a highly birefringent photonic crystal fibre with a 0.4 bar pressure resolution and a 10 cm spatial resolution. ...

Optical Society of America2018

Exploring the use of native spider silk as an optical fibre for chemical sensing

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

A spider uses up to seven different types of silk, all having specific functions, as building material, weapon and sensory organ to detect the presence of preys on its web. Recently, scientists have put under the limelight the extraordinary properties of t ...

IEEE Institute of Electrical and Electronics Engineers2018

From Spider Webs to a Biomimetic Optical Fibre Sensor

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

Can we use spider silk threads as natural, biological optical fibre sensors? In this communication, we will see how we can harness the optical properties of spider dragline silk and use it for sensing. ...

2018

CO2-filled Hollow-Core Fiber Reference Gas Cells for Laser Frequency Stabilization at 2 um

Luc Thévenaz, Kenny Hey Tow

We present different configurations of compact CO2 reference gas cells based on hollow-core photonic crystal fibers (HC-PCF) for laser frequency stabilization at 2 um. Gaseous helium permeation through the silica fiber walls was used to fabricate low-press ...

2018

All-fiber molecular frequency reference at 2 μm based on a versatile laser modulation sideband locking and a hollow-core fiber gas cell

Luc Thévenaz, Kenny Hey Tow

Sensing of atmospheric trace gases is crucial for climate monitoring and to predict global climate changes. The required global coverage and spatial resolution have driven the studies of space-borne differential absorption lidar (DIAL) instruments to remot ...

IEEE2017

Distributed photothermal measurements of gas presence along holey optical fibers

Luc Thévenaz, Kenny Hey Tow

Chirped-pulse phase-sensitive optical time domain reflectometry has shown a remarkable performance when applied to dynamic measurements of strain and temperature, recently reaching ranges of several kilometers while interrogating the fiber at acoustic freq ...

SPIE2017

Distributed photothermal spectroscopy in microstructured optical fibers: towards high-resolution mapping of gas presence over long distances

Luc Thévenaz, Kenny Hey Tow

Chemical sensing using optical fibers is often challenging, as it is generally difficult to achieve strong interaction between the guided light and the analyte at the wavelength of interest for performing the detection. Despite this difficulty, many scheme ...

Optical Society of America2017

All-fiber versatile laser frequency reference at 2μm for CO2 space-borne lidar applications

Luc Thévenaz, Kenny Hey Tow

We present a frequency stabilized laser at 2051 nm based on a versatile all-fibered stabilization setup. A modulation sideband locking technique is implemented to lock the laser at a controlled frequency detuning from the center of the CO2 R(30) transition ...

Springer Wien2017

From spider webs to a fibre-optic chemical sensor

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

From the spider’s perspective, silk is not only a building material but also a safety net, a weapon and a sensory organ to detect the presence of prey on its web. For scientists, dragline silk - directly extracted from spiders - is a tough, biodegradable a ...

2016

Weaving our way towards a new generation of ﬁbre-optic chemical sensors based on spider silk

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

From the spider’s perspective, silk is not only a building material but also a safety net, a weapon and a sensory organ to detect the presence of preys on its web. Indeed, this primeval material has been shaped over hundreds of millions of years by spiders ...

Ieee2016

Compact fibre Bragg grating-based thermometer for on-line temperature monitoring of drill bits

Luc Thévenaz, Kenny Hey Tow

In this communication, a novel compact fibre Bragg grating-based thermometer for on-line temperature monitoring of drill bits is reported. Our proposed technique can potentially be used to optimize any drilling process, requiring the use of small drill bit ...

SPIE2016

Towards a new generation of fibre-optic chemical sensors based on spider silk threads

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

A spider uses up to seven different types of silk, all having specific functions, to build its web. For scientists, native silk - directly extracted from spiders - is a tough, biodegradable and biocompatible thread used mainly for tissue engineering and te ...

Ieee2016

Towards a novel "silky" way to detect chemical species using spider threads

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

Silk possesses extraordinary properties that scientists are currently working hard on harnessing. Amongst them, this primeval material has shown early potential of having excellent optical properties. Through a regeneration process, it is possible to obtai ...

2016

Shedding light on the optical properties of spider silk fiber

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

Optical characterisation of a Nephila edulis spider dragline silk is performed. The silk fiber transmits light up to 1400 nm with a propagation loss of ∼9 dB/cm and birefringence of 8×10−3 measured at 1302 nm. ...

IEEE2015

Mapping the Uniformity of Optical Microwires Using Phase-Correlation Brillouin Distributed Measurements

Luc Thévenaz, Marcelo Alfonso Soto Hernandez, Andrey Denisov, Desmond Chow Ming Chia, Kenny Hey Tow, Joël Cabrel Tchahame Nougnihi

The distributed Brillouin gain profile of an ultrathin optical microwire made of chalcogenide-glass is characterized using a phase-modulated correlation-domain measurement technique. Method resolves variations of uniformity below 5% along a 13 cm-long micr ...

OSA2015

Spider silk: a novel optical fibre for biochemical sensing

Luc Thévenaz, Isabelle Dicaire, Desmond Chow Ming Chia, Kenny Hey Tow

Whilst being thoroughly used in the textile industry and biomedical sector, silk has not yet been exploited for fibre optics-based sensing although silk fibres directly obtained from spiders can guide light and have shown early promises to being sensitive ...

SPIE2015