Presentation ph d

transcript

Innovative fiber optic sensors: from theory to applications

Daniele Tosi

PhD presentationElectronics Engineering2008-2009

Overview

Sensor networks market

Optical fiber sensors

Grating sensors

Low-cost solutions

Principles

Processing

Results

Potential

Daniele Tosi, daniele.tosi@polito.it

Daniele Tosi - daniele.tosi@polito.it

Sensor for measurement of mechanical and physical parameters• Direct: strain, vibrations, temperature, ...

• Indirect: pressure, rotation, resonance, modes, level, ...

Network

Applications

Cost control

Near future scenario

VSWireless Sensor Networks Fiber Optic Sensors

Market size

#!!(" #!!%" #!!)" #!!&" #!!*" #!'!" #!''"

Market size

#!!(" #!!%" #!!)" #!!&" #!!*" #!'!" #!''"

./,"!"#

!)# !*# !+# !,# $!# $$#

Wireless

Global market

Market growth

Market size

#!!(" #!!%" #!!)" #!!&" #!!*" #!'!" #!''"

51% 49%Revenues

# units

WSNFOS

2008 2011

Market size

#!!(" #!!%" #!!)" #!!&" #!!*" #!'!" #!''"

TelecomSensors

$335MWi-fi Sensors

Near future scenarioC

TargetGen. Spec.

Differentiation

FOS WSN

Size ∅ <1mm 6x4x3 cm

Immunity Fiber immune to EMI

Active and passive interference

Distribution Distrib. + multiplex + punctual

PunctualSlow multiplex

Attenuation 0.2 dB/kmRemote sensing

WiLD < 1kmSmall cover area

Sensitivity

Cost$100 $1k $10k $100k $1M

100 nm

10 µm

1 mm POF

Doppler/TOF

Active fibers

Raman/Brillouin

CCD/imaging

Interferometry

Research papers

Revenues

Sensitivity

Cost$100 $1k $10k $100k $1M

100 nm

10 µm

1 mm POF

Doppler/TOF

Active fibers

Raman/Brillouin

CCD/imaging

Interferometry

FBG principles

FBG ➙ refractive index modulation inside the core of an optical fiber - wavelength/selective

FBG principles

Modulation period sensitive to:- mechanical strain- thermal expansion

Strain

Temperature

FBG principles

Strain (με)

1 pm/µε10 pm/°C{

FBG principles

Strain (με)

1 pm/µε10 pm/°C{

➙ Temperature compensation

FBG sensors

SourceReceiver

FBG arrays

...Coupling

FBG sensors

SourceReceiver

FBG arrays

?Coupling

FBG sensors

SourceReceiver

FBG arrays

?Coupling

FBG sensors

SourceReceiver

FBG arrays

?Coupling

Intensity detection

SourceReceiver

FBG arrays

...Coupling

FBG sensors

Sensitivity

Cost$1k $10k $100k $1M

Interferometry

FBG analyzer

Active fibers

Optical spectrum

Scanning filter

Intensitybased

FBG sensors

Sensitivity

Cost$1k $10k $100k $1M

Interferometry

FBG analyzer

Active fibers

Optical spectrum

Scanning filter

Intensitybased

Applications

• performance

• environment

• immunity

• safety

• invasiveness

Applications

• performance

• environment

• immunity

• safety

• invasiveness

Applications

• performance

• environment

• immunity

• safety

• invasiveness

Applications

• performance

• environment

• immunity

• safety

• invasiveness

Applications

• performance

• environment

• immunity

• safety

• invasiveness

Applications

Remote structuresSmart structuresSecurityIndustrial processSeismicAerospaceMilitaryMedical

FBG sensors

TargetGen. Spec.

Matched FBGs

Sensing Fixed

∫(·) ➥ power meter

Intensity modulation

Matched FBGs

0.18 mV/µε

320 µε

Matched laser

Backreflection

Matched laser

-150 -50 50 150

Strain

60µε

10 mV/µε

1 mV/µε

Commercial FBGA

Performances

M. FBGs M. Laser FBGA

Sensitivity ✓✓ ✓✓✓✓✓ ✓✓

Resolution ✓✓✓✓✓ ✓✓✓✓✓ ✓✓

Range ✓✓✓✓ ✓✓ ✓✓✓

# Sensors ✓✓✓ ✓✓ ✓✓✓✓✓

Stability ✓✓✓ ✓ ✓✓✓✓✓

Performances

M. FBGs M. Laser FBGA

Sensitivity ✓✓ ✓✓✓✓✓ ✓✓

Resolution ✓✓✓✓✓ ✓✓✓✓✓ ✓✓

Range ✓✓✓✓ ✓✓✓ ✓✓

# Sensors ✓✓✓ ✓✓ ✓✓✓✓✓

Stability ✓✓✓ ✓ ✓✓✓✓✓

Daniele Tosi - daniele.tosi@polito.itStatic

Dynamic

Performances

Perform. Optical

Min SNR -10 dB

Sensitivity 800 nε

RMSE 2.2 µε

Overhead 0%

Signal processing

Sensitivity

Cost$1k $10k $100k $1M

Interferometry

FBG analyzer

Active fibers

Optical spectrum

Scanning filter

Intensitybased

Signal processing

f/3kHzμε

PSD(dB)

D. Tosi, M. Olivero, G. Perrone, “Self-mixing based interrogation techniques for high-reflectivity fibre Bragg grating sensors”, Electronic Letters, vol. 44, 2008.

Time(s)

Noise properties - FBG backreflection

Signal processing

Adaptive filter - RLS 40 taps

Training

Acquired

Filtered

Reference

Signal processing

Adaptive filter - RLS 40 taps

Noise filtering

Acquired

Filtered

Reference

Signal processing

Capon power spectral density estimatorJ. Capon, “High-resolution frequency-wavenumber spectrum analysis”, Proc. IEEE, vol. 57, 1969.

FFT Param. Capon

SNR -10 dB <-40 dB -25 dB

Resolution 1/N ~<1/N Unlimited

Properties None Required Adaptive

Signal processing

Capon power spectral density estimatorJ. Capon, “High-resolution frequency-wavenumber spectrum analysis”, Proc. IEEE, vol. 57, 1969.

FFT Param. Capon

SNR -10 dB <-40 dB -25 dB

Resolution 1/N ~<1/N Unlimited

Properties None Required Adaptive15 dB

Performances

Perform. Optical Optical + SP

Min SNR -10 dB -39 dB

Sensitivity 800 nε 5.6 nε

RMSE 2.2 µε 0.4 µε

Overhead 0% <1%

Climaticchamber

Strain

Circuit

Temperature

Climatic chamber Outdoor

Temperature

Climatic chamber Outdoor

➙ Temperature compensation

Vibrations

Aluminum bar

Vibrations

POF sensorFBG

Surface wall

Vibrations

Wooden board

27.1 Hz

Acquisition

Laser/TEC

WVF generator

Matlab sound

DAQ card FBG

Speaker Receiver

Voice recognition

Cepstrum ➙ FFT[Capon(voice)]

Metronome

www. metronomeonline.com

144 bpm112 bpm92 bpm

Heartbeat

Criticalities:- FBG positioning- signal processing

69.9bpm

Potential

Remote structuresSmart structuresSecurityIndustrial processSeismicAerospaceMilitaryMedical

Potential

Smart structures

Distributed sensor networksFew sensing points, repeated

Potential

Remote sensingLower cost solutions

Remote structures

Potential

2%Medical equipment

Increase smartness capabilityReplacement / redundancy

Potential

22%15%

Niche applications in adjacent fields

Conclusion

• Fiber optic sensors market: trends and opportunities

• Applications range and requirements

• The proposed solutions - low cost FBG sensors

• The effect of signal processing

• Experimental results and potential developments

References

(1) D. Tosi, M. Olivero, G. Perrone, “Dynamic strain measurement system with fiber Bragg gratings and noise mitigation techniques”, Measurement Science and Technology, vol. 20, 2009.

(2) D. Tosi, M. Olivero, G. Perrone, “A low-cost fiber Bragg grating vibro-acoustic sensor for voice and heartbeat detection”, Applied Optics, vol. 47, 2008.

(3) D. Tosi, M. Olivero, G. Perrone, “Self-mixing based interrogation techniques for high-reflectivity fibre Bragg grating sensors”, Electronic Letters, vol. 44, 2008.

(4) D. Tosi, M. Olivero, G. Perrone, “Broadband source-based interrogation scheme of fiber Bragg grating sensors for structural health monitoring”, Key Engineering Materials, vol. 347, 2007.

(5) D. Tosi, M. Olivero, G. Perrone, “Optical microphone with fiber Bragg gratings and signal processing techniques”, Proc. SPIE, vol. 7098, 2008.

(6) D. Tosi, M. Olivero, G. Perrone, “Low-cost fiber Bragg grating-based static and dynamic strain system for structural monitoring”, Proc. SPIE, vol. 7098, 2008.

References

(7) Y. J. Rao, “In-fibre Bragg grating sensors”, Measurement Science and Technology, vol. 8, 1997.

(8) A. Othonos, K. Kalli, Fiber Bragg Gratings: Fundamentals and Applications in Telecommunications and Sensing, Artech House, 1999.

(9) W. W. Morey, “Distributed fibre grating sensors”, Proc. OFS Conference, 1997(10) F. A. Bezombes, M. J. Lalor, D. R. Burton, “Contact microphone using optical fibre

Bragg grating technology”, J. Phys. Conf. Ser., vol. 76, 2007.(11) A. Zaknich, Principles of Adaptive Filters and Self-Learning Systems, Springer, 2000.(12) J. Capon, “High-resolution frequency-wavenumber spectrum analysis”, Proc. IEEE,

vol. 57, 1969.(13) D. B. Huff, M. S. Lebby, “Fiber optic sensing technology: emerging markets and

trends”, Proc. SPIE, vol. 6619, 2007.(14) www.smartech.ch(15) www.bayspec.com (16) www.xbow.com

Acknowledgments

Julia GillardTracy HarrisSebastian Sabogal

Gaetano PellicanoBarbara PizzellaMaria Grazia Quieti

Armen Berjikly

Jake Wall

Guido Perrone

Massimo Olivero

Renato Orta

Alberto Vallan

Ivo Montrosset

Francesco Profumo

Claudio Maccone

+ others...

Antonio StrumiaSilvio Abrate

Barry PosnerKevin HolmesNick KurnsTerri GriffithMary Furlong

John CanningMattias AslundKevin CookMike Stevenson

EndThank you for your interest

Spectral response

Matched laser

Signal processing

Data modellingRMSE reconstruction:

11.4με ➙ 0.32με

(6 iterations)

D. Tosi, M. Olivero, G. Perrone, “Dynamic strain measurement system with fiber Bragg gratings and noise mitigation techniques”, Measurement Science and Technology, vol. 20, 2009.

FBG inscription

Matched FBGs

∫(·)

Matched FBGs

∫(·)

Power(strain)

Presentation ph d

Business