Fibre optics and applications

Fibre optics and applications (FOA)

Presentation of FOA

The Fibre Optics and Applications (FOA) team designs, manufactures and studies specialty optical fibres for devices with applications in telecommunications, metrology, original laser sources for industry, biomedical or environmental monitoring. To optimize the performance of these components and subsystems we study the properties of the fibre materials and their modifications resulting from nano-structuring or doping operations, in particular rare-earth ions. The properties of the dopants in these materials depend on their environment and can be modified by the radiation to which they are subjected. These modifications are also studied in aging experiments (degradation under irradiation), sensitivity to power (optical damage, photo-induced attenuation). The team relies on the fibre optics manufacturing platform and its optical and spectroscopic characterization equipment.

FOA team has various research directions:

Axis #1 : Specialty optical fibre components and systems

Axis #2 : Nanoparticles in  optical fibres

Axis #3 : Optical fibres in radiative environment


Axis #1: Specialty optical fibre components and systems

Leader : Dussardier Bernard

 Principal collaborations: GeoAzur (Valbonne), ILM (Lyon), IIT-Delhi & IIT-Roorkee (India), COPL (Quebec, Canada), University of Hull (U-K), INRAE-SPO (Montpellier)

 Financial supports: CNRS, UCA, GIS GRIFON, W. Doeblin Institute, Sentinelle Nord (Quebec),

 Technology platforms: Optical fibre fabrication center

 Description :

There is a very strong growth in the variety of application areas of specialty optical fibres as passive or active components in optical devices (lasers sources, sensor systems, etc). These components offer ever more original functions, and ever better technical and/or performances efficiency. It is also frequently necessary to integrate several of these functions in a single optical fibre. Currently, several paradigms of fibre optic systems are revisited in order to meet future needs.

The Optical Fibre team is involved in projects on designing, fabricating and characterizing of specialty optical fibres based on original concepts, often inspired by results from more fundamental projects of the team, with clearly identified potential applications.

The team has numerous collaborations and a rich network of external collaborators. Its core work is based on the technology platform “Optical fiber fabrication center” located at INPHYNI premises and run by its staff and the FOA team members.


Optical physics, guided-wave optics, photonics, optical fibres, rare-earth, spectroscopy, lasers, amplifiers, sensors


Axis #2 : Nanoparticles in optical fibres

Leader : Wilfried Blanc

Principal collaborations: LPhiA (Angers), ICGM (Montpellier), IPGP (Paris), CP2M (Marseille), CRHEA (Valbonne), CEMEF (Valbonne), CCMA (Nice), BIC (Bordeaux), GPM (Rouen), CEMES (Toulouse), ICI (Nantes), CNR-IFN Trento (Italie), Université de Clemson (USA), Université de Nazarbayev (Kazakhstan), Université de Tampere (Finlande), IPE (République Tchèque), CAMECA (USA), ZEISS (USA), ...

Financial supports: ANR, CNRS, UCA, W. Doeblin Institute, ...

Technology platforms: Optical fibre fabrication center

Description :

Since the pioneering work carried out in the 1960s which led to the production of the first transparent optical fibers, the performance of these waveguides is intimately linked to the development of innovative materials and processes. Until now, research has mainly focused on the development of a "perfect" glass, i.e. with a minimum of spatial fluctuations in composition (to limit the light scattering and therefore obtain the most transparent fiber) or with a doping in rare earth ions the most homogeneous (without formation of clusters of these ions, to limit the energy transfers deleterious for the lasers and the amplifiers). Contrary to this trend, a new family of optical fibers containing nanoparticles is developed at INPHYNI (Figure 1) [1]. This study is based on an understanding of the formation of nanoparticles, the development of innovative processes and the development of applications.

Figure 1: SEM image. Cross-section of an optical fiber containing nanoparticles in the core section.

Nanoparticle formation

Each fiber is obtained by hot drawing of a preform prepared by the MCVD process. Nanoparticles are formed by introducing, during the solution doping of the porous layer, either nanoparticles (LaF3, ZrO2, etc., doped or not with rare earth ions), or elements such as alkaline earths (Mg, Ca , etc) which trigger phase separation mechanisms. An important part of our activity consists in monitoring the evolution of the nanoparticles introduced as well as the formation of nanoparticles by phase separation. We have shown that, contrary to what is predicted by classical nucleation theory, the composition of nanoparticles changes with their sizes (Figure 2) [2]. This result was highlighted by CNRS.

Figure 2: variation in Mg and P concentration in nanoparticles measured by Atom Probe Tomography [2].

Innovative process: fragmentation during drawing

We were also the first to report that drawing step controls the size and shape of the nanoparticles in the fiber. The particles, spherical in the preform, tend to elongate during drawing (Figure 3). This elongation can lead to fragmentation (Rayleigh-Plateau instability) and is similar to a top-down process: a “large” particle in the preform can give rise to several “small” nanoparticles in the fiber [3].

Figure 3: 3D reconstruction of an optical fiber core containing nanoparticles. The images were obtained by SEM/FIB. The drawing axis is vertical. Nanoparticles formed by elongation-fragmentation are highlighted (red circle) [3].


  • Fiber lasers and amplifiers

Silica has characteristics which can be detrimental for luminescent ions (high phonon energy, poor solubility of luminescent ions, etc.). In order to overcome them, the encapsulation of luminescent ions within nanoparticles makes it possible to modify their atomic environment and to obtain new properties which would not appear in silica. For example, the insertion of the rare earth ion Er3+ within magnesium-based nanoparticles makes it possible to widen the emission band centered at 1.55 μm of interest for the amplifiers used in the telecommunications field (Figure 4) [4]. A 1.8 µm fiber laser was produced by doping with ZrO2:Tm3+ nanoparticles [5].

Figure 4: Emission spectra of Er3+ in the wavelength region of interest for telecommunications. The insertion of Er3+ within the nanoparticles leads to a broadening of the emission spectrum compared to the fiber without nanoparticles.

  • Sensors

The nanoparticles within the core of the optical fiber backscatter light. Thanks to the Optical Backscatter Reflectometry (OBR), it is possible to measure a spectral shift linked to a change applied to the fiber. Temperature, pressure or chemical or biological environment sensors have been developed [6]. “Nanos” fibers have the advantage to avoid the photo-writing of reflective elements such as a Bragg gratings. A major interest of these “nanos” fibers is to allow the development of spatial multiplexing detection systems with a millimeter spatial resolution (Figure 5).


Figure 5: Example of a 3D shape sensor made using optical fibers containing nanoparticles. Four fibers are placed around the needle. The measurements of back-scattered light make it possible to account for the deformation of the needle in real time [7].

[1] A. Veber et al., “Nano-Structured Optical Fibers Made of Glass-Ceramics, and Phase Separated and Metallic Particle-Containing Glasses”, Fibers, 7(2019)105
[2] W. Blanc et al., “Compositional Changes at the Early Stages of Nanoparticles Growth in Glasses”, Journal of Physical Chemistry C, 123(2019)29008
[3] M. Vermillac et al., "Fiber-draw-induced elongation and break-up of particles inside the core of a silica-based optical fiber", Journal of the American Ceramic Society, 100(2017)1814
[4] W. Blanc et al., “Fabrication of rare-earth doped transparent glass ceramic optical fibers by modified chemical vapor deposition”, Journal of the American Ceramic Society, 94(2011)2315
[5] P. Vařák et al., “The Preparation and properties of Tm-doped SiO₂-ZrO₂ phase separated optical fibers for use in fiber lasers”, Optical Materials Express, 10(2020)1383
[6] M. Sypabekova et al., “Reflector-less Nanoparticles Doped Optical Fiber Biosensor for the Detection of Proteins: Case Thrombin”, Biosensors and Bioelectronics, (accepté, 2020)
[7] A. Beisenova et al., “Distributed fiber optics 3D shape sensing by means of high scattering NP-doped fibers simultaneous spatial multiplexing”, Optics Express 27(2019)22074


Axis #3 : Optical fibres in radiative environment

LeadersMourad Benabdesselam & Franck Mady

The studies carried out in the team deal with the problem of the effects of radiation in silica optical fibres through various projects. The effects induced by radiation are characterized by radio-luminescence (RL) or stimulated luminescence (TSL, OSL) techniques and by absorption spectrophotometry. All of these characterisations, in parallel with physical modeling, make it possible to account for the radio-induced processes in fibres as well as the physical mechanisms responsible for their degradation.

The type of optical fibres studied can be passive (when used as a sensor and for signal transport) or active as in the case of fibre systems (amplifiers, lasers ...).

All these fibres are capable of operating in severe radiative environment for the control and monitoring of radioactive waste storage (CERTYF & SURFIN projects), for space applications for intra- and inter-satellite communications (PARADYSIO & HAPOLO projects) and finally for  medical applications. In the latter, active fibre optic dosimetry, applied to all new and promising cancer treatment techniques (pulsed proton therapy and flash radiotherapy), is proposed as part of a new project (FIDELIO). The latter is part of a very close collaboration within the Claude Lalanne research federation (FCL, Fédération Claude Lalanne), between the INPHYNI laboratory and the Antoine Lacassagne Center (Nice).

Recent/present projects:

SURFIN: AAP ANR-ANDRA 2016 (PIA3): 10/2017 - 09/2021

Using TSL, OSL and RL , to study the dosimetric characteristics (sensitivity in dose and in dose rate) of vitreous materials or of radiosensitive silica-based optical fibres doped with active ionic species for the detection of radiations in plants under dismantlement or in waste storage sites.

Partners:  PhLAM Laboratory, University of Lille (leader); INPHYNI Laboratory, Côte d´Azur University; Hubert Curien Laboratory, Jean Monnet University of St Etienne; Clermont Institute of Chemistry, Clermont Auvergne University


CERTYF: AAP ANR-ANDRA 2016 (PIA3): 11/2017 - 10/2021

Manufacture, characterization and modeling of radio-induced attenuation (RIA) of different types of silica optical fibres, depending on their resistance to radiation (sensitive or tolerant) or simply of the telecom type. These different fibres are intended to be used as radiation sensors emitted in radioactive waste storage sites.

Partners: Hubert Curien Laboratory, Jean Monnet University of St Etienne (leader); INPHYNI Laboratory, Côte d´Azur University; Institute for Radiation Protection and Nuclear Safety (IRSN), Saclay


DROÏD: ANR-11-RSNR-0008 (RSNR call)  phase 1: 2013-2019 ; phase 2: 2019-2023)

Partners: PROMES-CNRS ( UPR 8521 ) (leader), Université de Perpignan Via Domitia, Perpignan

The objective of the DROÏD project is to contribute to the security of nuclear installations and to the radiation protection of personnel by developing a dosimetric monitoring method which allows the surveillance of part or all of an installation. This dosimetric network will be based on the very high sensitivity to ionizing radiation of specially developed optical fibres.

It will use the radiation-induced fiber attenuation, also called Radio-Induced Attenuation (RIA), interrogated at a distance using optical reflectometry, and will allow real time mapping and monitoring. Because the seeked application is toward the protection of staff, the project has a particular focus on increasing the RIA sensitivity of the fibres, as compared to usual fibre dosimeters.


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