Radiation Effects on Optical Fibers and Fiber-based Sensors Radiation Effects on Optical Fibers and

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  • Radiation Effects on Optical Fibers and Fiber-based Sensors

    Recent Advances and Future Challenges

    Sylvain Girard

    sylvain.girard@univ-st-etienne.fr

    Phone: +33 (0) 477 915 812

    CERN Seminar, Geneva, Sept. 27th, 2016 1

    mailto:sylvain.girard@univ-st-etienne.fr

  • Outline

    Review paper: S. Girard, J. Kuhnhenn, A. Gusarov, B. Brichard, M. Van Uffelen, Y. Ouerdane, A. Boukenter, and C. Marcandella, “Radiation Effects on Silica-based Optical Fibers: Recent Advances and Future Challenges”, IEEE TNS, vol.60 (3) 2015 - 2036, 2013

    • Introduction: Context of our work • Part 1: Basic mechanisms of radiation effects on optical fibers • Part 2: Recent Advances on radiation hardened optical fibers • Part 3: Recent Advances on radiation hardened fiber-based sensors • Part 4: Future Challenges

  • Introduction: Context of our work

  • Coating

    Cladding

    Core

    Amorphous silica

    Silica-based optical fibers (OFs) are made with pure or doped amorphous silica (a-SiO2) glass

     Telecom-grade optical fibers : Single-mode or Multimode  Polarization-maintaining optical fibers  Rare-earth doped optical fibers Microstructured optical fibers  Hollow core optical fibers  Plastic optical fibers

    In this talk, we focus on silica-based optical fibers for which the light guiding is ensured by Total Internal Reflection (TIR)

     Few modes optical fibers  Polarising optical fibers  IR-optical fibers (sapphire)

  • Silica-based optical fibers can be designed for light transmission from the ultraviolet to the IR part of spectrum (250 – 2µm)

    0.1 0.2 0.7 0.8 0.9 11 2 3 5 100.3 0.4 0.50.6

    12 10 8 6 4 2

    10 -2

    10 0

    10 2

    10 4

    10 6

    10 8

    10 10

    10 12

    Queue d'Urbach

    Défauts (?)

    Défauts induits par irradiation

    Impureté OH

    Diffusion ( -4 )

    A tt

    é n

    u a ti

    o n

    o p

    ti q

    u e (

    d B

    /k m

    )

    Défauts

    Energie du photon (eV)

    3 

    2.0 1.5 1.0 0.5 0.0

    Impureté OH

    Longueur d'onde (m)

    Queue multiphonon

    Diffusion

    2

    1310 nm

    1550 nm

    0.15

    4

    0.5

    Wavelength (µm) O

    p ti

    ca l a

    tt e

    n u

    at io

    n (

    d B

    /k m

    )

    Photon Energy (eV)

     Data links  Diagnostics

    • Laser • Plasma

     Fiber lasers  Fiber amplifiers  Sensing

    • Strain • Temperature • Dose • Gyroscopes

  • Since Fukushima event, OFS are more and more considered by nuclear industry

    Various OFS technologies exist, exploiting the a-SiO2 structural and optical properties

  • Vulnerability and hardening studies of OF and fiber-based sensors (OFS) in severe environments

    1. Electromagnetic immunity

    2. High bandwidth/ multiplexing capability

    3. Low attenuation

    4. Low weight and volume

    5. High temperature resistance

    1 Gy=100 rad

  • Part 1: Basic Mechanisms of Radiation Effects on Optical Fibers

  • 3 degradation mechanisms at macroscopic scale have been identified under irradiation

    1. Radiation-Induced Attenuation (RIA)

    2. Radiation-Induced Emission (RIE)

    3. Compaction

    Courtesy B. Brichard (SCK-CEN)

     The relative contributions of these 3 mechanisms depend on the radiation environment, on

    the targeted application and on the fiber properties

  • Radiation-induced mechanisms occurring at the microscopic scale in a-SiO2 have been identified…and are a bit complex

     Optically-active point defects are induced by irradiations. Their properties are responsible for the degradation of OFs

    Griscom D.L. SPIE vol. 541, 1985

    Aggregates:

    Colloids, Bubbles

    UV Light

    X Rays

    g Rays

    Fast

    Electrons Neutrons

    Fast Ions

    Electron-Hole

    Pairs

    Atomic

    Displacement

    I II III IV V

    Recombination

    Free Vacancies

    And Interstitial

    Free Carriers

    Recombination

    Light Emission

    Transient Defects

    Photolytic Defects

    Radiolytic

    Fragments

    (Principally H°)

    DIFFUSION-LIMITED

    REACTIONS

    CARRIER

    TRAPPING DEFECT

    FORMATION

    EXCITED STATE

    RELAXATION

    RCOMBINATION

    IRRADIATION PROMPT

    OCCURRENCE

    (Compton Electrons)

    (Secondary

    Electrons)

    Trapping at

    Radiolytic Defects

    Trapping at

    Preexisting Defects

    Trapping at

    Impurities

    Trapping at

    Knock-on damages

    Dimerization

    Self-trapping

    Further Diffusion-

    Limited Reactions

    Stabilization by

    diffusion of charge-

    compensating Ions

  • Optical and energy properties of these point defects explain the complexity of the OF radiation-response

    STH1

    STH2

    POR

    NBOHC

    E '

    ODC

     Each parameter affecting the stability, generation efficiency or optical properties of these point defects will affect the OF radiation response.

     Too complex to be yet predictable!

    L. Skuja; NATO Book Chapter, 2000

    Griscom D.L. SPIE vol. 541, 1985

  • Numerous parameters, intrinsic or extrinsic, influence the OF radiation response

     These parameters affect the RIA levels & kinetics that generally define the OF vulnerability

  • Fiber sensitivity strongly depends on the fiber composition: core dopants, process parameters are less impacting

    No ideal composition exists, their relative RIA levels depend on the radiation environments, fiber profile of use…

  • Fiber sensitivity strongly depends on the fiber composition: cladding dopants, stœchiometry, impurities, …

    • A slight change in composition strongly changes the nature, concentration and stability of induced defects

    2 Telecom SMF  same reference and different cladding compositions

    0 500 1000 1500 2000 2500 3000 3500 4000 0

    3

    6

    9

    12

    15

    R IA

    ( d

    B /k

    m )

    Time (s)

    SM_GeP

    SM_Ge

    0.8 MeV neutrons

    5x10 13

    n/cm²

    1550nm

    0 500 1000 1500 2000 2500 3000 3500 4000 0

    3

    6

    9

    12

    15

    R IA

    ( d

    B /k

    m )

    Time (s)

    SM_GeP

    SM_Ge

    0.8 MeV neutrons

    5x10 13

    n/cm²

    1550nm

  • Fiber vulnerability: RIA growth kinetic depends on the harsh environment: dose, dose rate, T, irradiation duration,…

    Vulnerability strongly depends on the harsh environment associated with the application  what means COTS Rad Hard Fibers?

  •  Temperature parameter has been too poorly and badly studied (R+T instead R&T)

    Fiber vulnerability: RIA levels and kinetics depends on the temperature of irradiation

    S. Girard, et al., IEEE TNS, 60(6), pp. 4305 - 4313, 2013.

  • 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.0

    0.5

    1.0

    1.5

    2.0

    2.5

    R IA

    ( d

    B /m

    )

    Time (s)

    X-ray pulse

    RIA

    bleaching

    Ge-doped optical fiber

    1550nm, 51Gy

    Fiber vulnerability: RIA decay kinetic after irradiation  drive the fiber recovery between successive irradiations

     Majority of defects is unstable at the temperature of experiments  the RIA decreases with time after irradiation

     The bleaching kinetics and efficiency depend on many parameters: wavelength and power levels of the injected signal, …

    H. Henschel et al., IEEE TNS 49, 2002

    Influence of injected light power

    0.1µW

    1µW

    38µW

  • Part 2a: Recent Advances on radiation hardened optical fibers

  • CERN LHC: identification of a radiation hardened SMF @1310nm (steady state, 100 kGy dose level)

    • F-doped fiber + ? • Very complex

    radiation response • Strongly dependent

    on irradiation conditions

    T. Wijnands, et al., JLT 29, 3393-3400 (2011) T. Wijnands, et al., IEEE TNS. 55, 2216-2222 (2008)

  • ITER diagnostics: RIA mitigation techniques can be applied to reduce the fiber sensitivity for given application and radiation environment

     For some applications, loading of the fiber with H2, (D2 or O2) can reduce the RIA

    wavelengths: difficult to predict too!

    Low OH silica without H2

    R I A

    [ d

    B /

    m ]

    Low OH silica with H2

    R I A

    [ d

    B /

    m ] POSITIVE IMPACT

    NEGATIVE IMPACT

  •  Characterize, reduce the component vulnerability (EMP and radiations): electronics (CCD, transistor, memory,...), optics (fiber optics, glasses), CMOS image sensors (ISAE-CEA-LabHC)

    2m thick outer wall to protect outside workers and adjacent buildings

    X-rays 14 MeV n g-rays

    Monte Carlo Simulation of dose a