Cedric Perrotton

A reliable, sensitive and fast optical fiber hydrogen sensor based on surface plasmon resonance.

We report for the first time on the experimental response of a Surface Plasmon Resonance fiber optic sensor based on wavelength modulation for hydrogen sensing. This approach of measuring the hydrogen concentration makes the sensor insensitive to intensity fluctuations. The intrinsic fiber sensor developed provides remote sensing and enables the possibility of multi-points sensing. The sensor consists of a multilayer of 35 nm Au/180 nm SiO2/Pd deposited on a step- index multimode fiber core. The sensitivity and selectivity of the sensor are optimal at a Pd thickness of 3.75 nm. The sensor is sensitive to a hydrogen concentration ranging between 0.5 and 4% H2 in Ar, with a response time less than 15 s.

Wavelength response of a surface plasmon resonance palladium-coated optical fiber sensor for hydrogen detection

An optical fiber using palladium as sensitive layer is characterized in the range of 450 to 900 nm. The sensitive layer is deposited on the outside of a multimode fiber, after removing the optical cladding. The sensor is based on a measurement technique that uses the surface plasmon resonance effect. A continuous change in output intensity is observed as a function of the hydrogen concentration between 0.5% and 4% H2 by volume in Argon. The response shows that the transmitted intensity can either decrease or increase, depending on the selected wavelength. This behavior is directly related to the change in reflectance upon hydrogenation between the polarization s and p. The loading time is 30 s and the unloading time is 90 s in a mix of argon and 10% of oxygen. The detectors show a good reproducibility.

Hydrogen leak detection: a comparison between fiber optic sensors based on different designs

We present a review of optical fiber hydrogen sensors based on Palladium. Palladium hydrogen optical fiber sensing system can be considered as a model for other metal hybrid system. Besides, the Palladium hydrogen, systems are well characterized in bulk, cluster or thin film form. We focus on the fiber principles. We discuss then their performances regarding their configurations. We will conclude by introducing the challenges for designing an ideal hydrogen optical fiber sensor based on metal hybrids approach and which designing direction seen the best to take.

Review of optical fiber sensor technologies for hydrogen leak detection in hydrogen energy storage

We introduce a review concerning hydrogen sensors already validated based on palladium, and we discuss the best ways to proceed to achieve an ideal hydrogen sensor. We discuss the performances regarding the configuration of an optical fiber hydrogen sensor as well as the used materials properties. We conclude that hydrogen sensors using plasmonic effects are a seductive way to follow.

Study of a fiber optic sensor for hydrogen leak detection

We present a study of a fiber optic sensor for leak detection based on Surface Plasmon Resonance (SPR). We use Palladium as the sensitive material for hydrogen detection. In this configuration, the transducer layer is a multilayer stack made of a silver, a silica and Pd layer. The spectral modulation of the light transmitted by the fiber allows to detect hydrogen on the environment. The multilayer thickness defines the sensor performance. The silica thickness tunes the resonant wavelength whereas the silver and Pd thickness determines the sensor sensitivity. The study of the sensor performance as function of several thicknesses (Pd/Si/Ag) is achieved and we present the optimal configuration at a concentration of 4% hydrogen in argon.

Solid material rigidity modulus measurements by a nondestructive optical method: application to electrical steering system

We propose a new non destructive optical method for the determination of the shear modulus G of solid materials. The shear modulus is determined by measuring the twisted angle θ as a response of the material sample, depending on an applied force. The measuring of this twisted angle is obtained by using an adapted polarimetric sensor. The effective measurements of rigidity modulus G for different materials were experimentally achieved, we obtained respectively 1.4464.1010 N/m2, 0.99417.109 N/m2 and 1.0395.1011 N/m2 for Aluminum, PMMA and Steel. The study has demonstrated the effective usefulness of our method for evaluating the rigidity modulus. A good agreement between the theoretical and experimental results was achieved. This study permit to design and elaborate a new type of optical torque sensor for electrical power assisted steering system.

A distributed optical fiber sensor for hydrogen detection based on Pd, and Mg alloys

An optical fiber containing structured hydrogen sensing points, consisting of Palladium and/or Magnesium alloys is proposed and characterized. The sensitive layer is deposited on the outside of a multimode fiber, after removing the optical cladding. The sensor is based on a measurement technique which uses the Surface Plasmon Resonance effect. Compared to previous work which was performed at a single wavelength of 670nm, this study was done in the range of 450 to 900nm. A continuous change in intensity is observed as a function of the hydrogen concentration between 0.5% and 4% H2 in Ar. The response shows that the intensity transmitted can either decrease or increase, depending on the selected wavelength. The response time and the reproducibility of the detectors are also discussed. From our experiments and optical simulations we conclude that Pd covered indicator layers based on Mg alloys, such as Mg-Ti, would be even more advantageous compare to Pd layers thanks to their lower hydrogen equilibrium pressures. We will demonstrate an extended sensitivity range by juxtaposing different materials over a fiber section, having different hydrogen equilibrium pressures.

Design, study, and achievement of a fiber optic amplitude modulation sensor for angular position detection: application to an automotive steering sytem

The reliable, accurate and low cost measurement of angular position is an important challenge for numerous industries such as aerospace or automotive industries. We propose a new optical fiber angular position sensor connected to an automotive power steering column. This sensor allows the measurement of the angular position of a car steering wheel over a large range (± 3 turns of wheel). The wheel rotation induces micro-bending in the transducer part of the optical fiber sensing system. This system operates as an amplitude modulation sensor based on mode coupling in the transducing fiber in the case when all the modes are equally excited. We study the sensors response both theoretically and experimentally with a multimode step index optical fiber [Rf (fiber radius) = 300μm; rc (core radius) = 50μm; nc (core index) = 1,457; N.A. = 0, 22 and the wavelength is 632, 8 nm at the ambient Temperature (20°C)]. This sensor has been tested between (-3x360) and (+3x360) degrees with 0,147 sensitivity. We show that the sensitivity can be controlled as a function of the sensors length and the study of the sensors output power as a function of the angular position has been achieved. We compare modeling and experimental validation and we conclude by a perspective of what could be soon an industrial sensor.