Amplificateurs Optique pour L'Espace

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Title
Isochronous Annealing Experiment Applied To
Erbium Doped Fiber For Spatial Application
IES Institut dElectronique du Sud
L. Troussellier C. Chluda
L. Dusseau P. Signoret
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Presentation outline

• Introduction Background
• Various applications of Erbium Doped Fiber
• Aim of this work
• First Part Theory
• Radiation sensivity of glasses
• Recovery
• Second Part Experiments and results
• Irradiation
• Annnealing
• Conclusion Perspectives

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Introduction
Why studying ?
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Example of Application for a spatial EDFA
Satellite optical link
Lidar ( LIght Detection And Ranging )
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Radiation effect on optical fiber
Additional absorption of light ? Radio
Induced Absorption (RIA) ? Efficiency ,
system failure

• irradiation parameters
• Dose (Time)
• optical parameters
• Materials
• Wavelength
• Optical Power(Time)
• system parameters
• Temperature(Time)
• Fiber Length

RIA depends on
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Aim of this study
ARI

• Assessment under radiation
• Competition between
• Degradation (Dose)
• Recovery (Optical, Thermal)

T,P
D
Knowledge of RIA during the whole mission time
To spatial application Need  quick  procedure
to test device.
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Part 1
Degradation Recovery
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RIA origin
Degradation
Trap level creation in glasses
1/? Detrapping probability n(t) trapped
charge density
Recovery
1/ ? b Attempt to escape factor Etrap
Activation energy k Boltzmann constant T
Temperature
Detrapping
with
Arrhenius Equation
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Arrhenius Equation
Time - Temperature Equivalence
Thus 10 years at 25C
is equivalent at 1 hour à 167,85C
Isothermal experiment
But RIA during the mission ?
Isochronous experiment
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Isochronous Annealing
Increasing step temperature
Deeper and deeper levels are detrapped
Consequently the total RIA decreases
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Part 2
What we do
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Irradiation gt Degradation
Transmitted power spectra at each
dose deposit step.
Determination of total RIA at each dose step.
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Thermal annealing gt Recovery
Transmitted power spectra at each
temperature step.
Determination of RIA at each temperature step
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The aim of this procedure
10 days
10 years
Discrete irradiation
Extraction of Normalized Recovery as a function
of temperature and time.
Distributed Irradiation during 10 years
Assessment of RIA as a function of mission time
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Conclusion
Conclusion

• Usual test gt too conservative.
• Worst-case but more precise.
• Taking into account the recovery gt more optical
  fibers are selectable.

• Perspectives

• Better knowledge of recovery in oxyde
• Experiment to compare the co-dopant recovery
  possibilities.
• Addition of the photobleaching study

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Thank you for your attention