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A compact high precision Fabry-Perot interferometer for monitoring Earth deformation

0f828d1e52998fda294448484de2e409?s=47 @Résif
July 05, 2017

A compact high precision Fabry-Perot interferometer for monitoring Earth deformation

Présentation de Han Cheng Seat (INP-LAAS) au Workshop "Instrumentation Géophysique" | 3-5 juillet 2017, Brissac

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@Résif

July 05, 2017
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  1. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    Laboratoire conventionné avec l’Université Fédérale de Toulouse Midi-Pyrénées Han Cheng SEAT seat@enseeiht.fr M. Cattoen, F. Lizion, O. Bernal G. Ravet, L. Michaut Consortium ANR LINES & FUI MIRZA A compact high precision Fabry-Perot interferometer for monitoring Earth deformation RESIF Brissac 3 – 5 July 2017
  2. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    2 Summary 1. Extrinsic fiber Fabry-Perot interferometer (EFFPI) development ƒ Operating principles ƒ Modulation-based EFFPI sensor ƒ Characteristics 2. Fiber interferometric long-baseline hydrostatic leveling sensor (iHLS) 3. Fiber interferometric optical borehole tiltmeter (iOBT) 4. Fiber interferometric gravimeter (iGRAVI) 5. Fiber interferometric seismometer (iSISMO) 6. Conclusions & Perspectives RESIF Brissac 3 – 5 July 2017
  3. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    3 EFFPI Operating Principles Air cavity Sensing fiber R2 + Interference signal Collimator Δd R1 IS IR I Collimator λ=1310 nm Photodetector Fiber coupler or circulator Target object Sensing arm d Output arm DFB-LD RESIF Brissac 3 – 5 July 2017 ) cos( 2 θ Δ + + = S R S R I I I I I ) cos( 0 θ Δ + = m V V V d n p Δ = Δ λ π θ 4 Δθ calculated modulo π ⇒ directional ambiguities p = number of reflections
  4. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    4 Modulation-based EFFPI • Experimental schematic of modulation-based EFFPI sensor RESIF Brissac 3 – 5 July 2017 LD : Laser Diode FC : Fiber Circulator/Coupler ISO : Isolator TEC : Thermo-Electric Controller C : Collimator DAQ : Data AcQuisition PD : Photodetector SF : Sensing Fiber T : Target surface (mirror) d + Δd
  5. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    5 Modulation-based EFFPI: quadrature signals Phase diagram of in-quadrature signals Vy vs Vx Modulation f1 at 25 kHz & d ~25 mm ¾ Δi(t) ~0.48 mA ⇒Δλ ~4.3 pm • Generating quadrature interference signals ⇒ target direction Quadrature condition ( ) 0 cos x x mx V V V θ = + ( ) 0 sin y y my V V V θ = + 2 4 2 nd λ π θ π λ Δ ⎛ ⎞ Δ = = ⎜ ⎟ ⎝ ⎠ 2 1 8nd λ λ Δ = Vy and Vx quadrature pair Modulation at frequency f1 Multiplexed output interference signals RESIF Brissac 3 – 5 July 2017 n d 4 λ = Δ 1 interference fringe ⇒
  6. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    6 EFFPI for quasi-static displacments Lissajous phase diagram (Vy vs Vx ) Modulation f2 at ~1 Hz (d ~25 mm) ¾ Δi(t) ~1.94 mA ⇒ Δλ ~17.19 pm • Generating "reference displacement" ⇒ weak (λ/4) and quasi-static displacement or stationary target Demodulated Vy and Vx in quadrature Phase condition nd 2 1 2 ≥ Δ λ λ RESIF Brissac 3 – 5 July 2017
  7. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    7 EFFPI characteristics: static & dynamic “Static” displacement (step mode) ¾ precision ~2 nm (10-3– 500 Hz) ¾ range 2 nm – 5 µm (limited by PZT linearity) ¾ Inset: max. error (~46 nm) at PZT translation limit Dynamic displacement measured against PZT y V x V Dcalp = 5.155 µm Drefp = 5.153 µm 0.146 max D µm i = Δ 0.0073 D µm mean = Δ Dynamic displacement ¾ EFFPI amplitude ~5.155 µm (c.f. reference amplitude 5.153 µm) ¾ error ~2 nm (0.04%) • Displacement calibration against reference Polytec PI piezo-electric transducer RESIF Brissac 3 – 5 July 2017
  8. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    8 EFFPI characteristics: drift & stability Displacement measurements from Probe 1 and Probe 2 Difference displacement (Probe 1 – Probe 2) ¾ Probe 1 and Probe 2 displacements ~14 nm ¾ 16.5 mins of data extracted at 1 kHz ¾ Difference ‰ max: < 1 nm ‰ min: ~0.15 nm ¾ Possible causes: temperature-induced perturbations, wavelength variations • Drift & stability characterization with differential probes RESIF Brissac 3 – 5 July 2017
  9. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    9 EFFPI characteristics: temperature sensitivity • Temperature sensitivity: equivalent displacement Differential displacements Temperature variation Differential configuration in controlled temperature chamber ¾ relative temperature increase over ~1 hr period (~ 0.1 °C) ¾ temperature variation by independent sensor (AD592 temperature sensor: 3.9 mV/°C) ¾ Probe1 & Probe2 displacements ~25.82 nm ¾ thermal expansion of steel cage system ~25.6 nm (stainless steel 410 ~10.5 µm/m/°C) RESIF Brissac 3 – 5 July 2017
  10. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    10 Applications in Geophysics: ANR LINES RESIF Brissac 3 – 5 July 2017 • Development & installation of 3 instruments at LSBB test site since Feb 2012 LINES-related components for seismometer (iSISMO), bore-hole tilemeter (iOBT) and long baseline hydrostatic levelling sensor (iHLS) Borehole tiltmeter (iOBT) Long baseline hydrostatic leveling sensor (iHLS) Seismometer (iSISMO) LSBB geo-location in the Vaucluse
  11. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    11 Applications in Geophysics: iHLS RESIF Brissac 3 – 5 July 2017 iHLS ¾ liquid level variations ⇒ tilt ¾ typically 1 nrad ~variation of 1 mm/1000 km! ¾ combined baseline 150 m ¾ precision ~10-11 radians ¾ frequency domain: 10-5 – several Hz ¾ transfer to industry ongoing iHLS incorporating EFFPI in differential configuration Sensing fibers (2 x 270 m and 2 x 120 m) Differential optical probes iHLS LVDT reference sensor Target mirror Long baseline hydrostatic inclinometer • Fiber interferometric long-baseline hydrostatic leveling sensor (iHLS)
  12. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    12 iHLS response and noise level RESIF Brissac 3 – 5 July 2017 • iHLS frequence response: comparison with HLS-Fogale, LILY tiltmeter, GPS GPS measurement HLS 140 m Fogale capacitive sensor used by the CERN 150 m iHLS used at LSBB site LILY electrolytic borehole tiltmeter GPS measurement Summary of comparison ¾ frequency domain: 10-6 – 10-2 Hz ¾ from ~10-5 Hz ‰ iHLS ~10 times less noisy than HLS- Fogale ‰ iHLS >20 times better than LILY ¾ higher frequencies (from 10-2 Hz) ‰ iHLS ~100 times better than HLS- Fogale and LILY in precision ¾ iHLS also less sensitive to atmospheric noise compared to GPS systems & LILY (local pressure variations)
  13. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    13 iHLS for earth deformation & hydrology RESIF Brissac 3 – 5 July 2017 Long baseline hydrostatic inclinometry • iHLS for Earth deformation Earth deformation ¾ precision ~ 2 x 10-11 rad ¾ diff. iHLS – LVDT < 0.2% before quake ¾ diff. iHLS – LVDT ~3% during quake Earth tides Difference LVDT – iHLS LVDT & iHLS M8.7 Sumatra event
  14. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    14 iHLS for accelerator alignment at CERN RESIF Brissac 3 – 5 July 2017 • iHLS for particle accelerator & collider alignment at CERN Evaluation of iHLS at CERN TT1 test tunnel iHLS HLS Fogale TT1 (140 m long) iHLS HLS-Fogale (µm) (µm) (µm) 6.25 µm Comparison between iHLS-LINES and HLS-Fogale (stability) Detected earth tides Center West East 05/09/2016 10/09/2016 65 -15 15 -15 15 17/10/16 Results ¾ 3 iHLS deployed at CERN ¾ diff. ~ 6.25 µm at centre position ¾ continuous operation for iHLS but regular disruption to HLS-Fogale
  15. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    15 Applications in Geophysics: iOBT RESIF Brissac 3 – 5 July 2017 • Fiber interferometric optical borehole tiltmeter (iOBT) iOBT ¾ pendulumn principles ¾ tri-axial probes spaced at 120° ¾ d1 + d2 + d3 = constant ‰ redundancy measurement ‰ compensates atmospheric noise ‰ corrects for system drifts ¾ dynamic range ~ ±1 mm ¾ frequency domain: 10-3 – 10 Hz ¾ transfer to industry ongoing Tri-axial measurement of displacements d1 , d2 and d3 iOBT 3 Optical probes Sensing fibers (3 x 270 m) Moving mass Borehole (hidden) iOBT incorporating 3-axis EFFPI sensor probes iOBT in borehole
  16. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    16 iOBT response and sensitivity to earth tides RESIF Brissac 3 – 5 July 2017 Resultant response ¾ 0.6 Hz frequency band denotes fundamental oscillating mode ¾ 12 Hz and 26 Hz bands indicate rod’s vibration modes ¾ remaining frequency bands caused by parasitic movements • iOBT frequence response from squarewave excitation induced by PZT plate & earth tide detection Measurement of earth tides with iOBT over 10 days Resolution ~ 1 nm Filtered displacement Earth tide detection ¾ 10 days observation of earth tides ¾ displacement resolution ~1 nm ¾ corresponding tilt resolution ~1 nrad
  17. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    17 iOBT redundancy capability RESIF Brissac 3 – 5 July 2017 • iOBT: validation of redundancy via tri-axial displacement measurement Validation of redundancy capability ¾ M5.8 Japan earthquake 29 Feb 2012 ¾ d1 + d2 + d3 = ~ 10 nm over 800 s d1 + d2 + d3
  18. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    18 iOBT for earth deformation: 2D movement RESIF Brissac 3 – 5 July 2017 • iOBT for earth deformation iOBT response to seismic activities (M 6.1 Argentina earthquake) Earthquake observation ¾ Argentina earthquake 5 Mar 2012 ¾ magnitude ~M6.1 ¾ amplitudes ~15 - 24 µm (3-axis) Reconstructed 2D movement 2D movement Earth tides ¾ 2D observation ¾ orientation along N-S ¾ amplitudes ~80 130 nm (3-axis) Oscillation of iOBT with earth tides
  19. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    19 Applications in Geophysics: iGRAVI RESIF Brissac 3 – 5 July 2017 Drop chamber with sensor detecting free-falling mass iGRAVI preliminary results ¾ mGal precision (10-5 m/s2) under unoptimized laboratory conditions ¾ TRL 3 ¾ industrial partners: Aquitaine Electronique, etc time (ms) Displacement (µm) Displacement (µm) x(t) Measurement of g from free-fall of mass • Fiber interferometric gravimeter (iGRAVI) Measurement of x(t) to obtain g Response of x(t) during free-fall x = ½ g*t2
  20. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    20 Applications in Geophysics: iSISMO RESIF Brissac 3 – 5 July 2017 • Fiber interferometric seismometer (iSISMO) Mirror surface Collimator Toroidal joint Exploded view of L22 used in iSISMO iSISMO configuration/specifications ¾ based on L22 Hz seismometer ¾ mobile mass structure modified for interferometric probe ¾ L22 inductive output used as reference ¾ movement of mobile mass ‰ displacement ‰ velocity (or acceleration) upon differentiation ¾ resolution of iSISMO ‰ ~ 1 nm in displacement ‰ ~ nm/s in velocity ¾ application frequency domain: 2 – 5000 Hz (> 1Hz) iSISMO with 1 km fiber for remote sensing iSISMO at LSBB test site
  21. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    21 iSISMO response to natural oscillation RESIF Brissac 3 – 5 July 2017 • iSISMO frequency response 0 Frequency (Hz) DSP of displacement (dB): ref used 1 nm2/Hz DSP of displacement (dB): reference 1 nm2/Hz Frequency (Hz) Spectral analysis of oscillatory noise level over 0 – 5 kHz bandwidth (LAUM-ESEO results) iSISMO noise analysis ¾ typical operating range: 2 – 200 Hz ¾ noise level corresponds to precision of < 2 nm over 5 kHz bandwidth ¾ comparable to best commercial seismometer (Streckeisen STS2) -80 0 -70 -10 500 1000 1500 3500 4000 4500 5000
  22. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    22 Conclusions RESIF Brissac 3 – 5 July 2017 ¾ Precision: < 2 nm over 10–3 – 500 Hz bandwidth ¾ Dynamic range: 2 nm – ~8 mm at 4 mm/s (Nyquist limit) ¾ Alignment tolerance: > ± 1° (with < 10 nm error; double reflection) ¾ Stability & temperature sensitivity: 25–50 nm/°C (1-axis) & 1 nm/°C (differential) ¾ Basis for 4 opto-geophysics instruments: ¾ iHLS: resolution ∼10-11 rad over bandwidth of 0 – several Hz ¾ iOBT: resolution ∼1 nrad over bandwidth of 0 – 10 Hz (with tri-axial redundancy) ¾ iGRAVI: precision ~mGal (10-5 m/s2) ¾ iSISMO: displacement resolution < 1 nm & velocity resolution ~ 10-9 m/s over 2 Hz – 5 kHz bandwidth ¾ currently only relative measurement!
  23. LAAS-CNRS / Laboratoire d’analyse et d’architecture des systèmes du CNRS

    23 Perspectives & Future Work RESIF Brissac 3 – 5 July 2017 ¾ Technology transfer for industrial development & commercialization (work in progress FUI MIRZA) ¾ Laser wavelength locking to increase sensor resolution dynamic ¾ Low-power consumption for autonomous deployment ¾ Absolute measurement of distance (work in progress) Thank You