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OPTICAL SENSORS AND THEIR APPLICATIONS

PRESENTED BY GAURAV PURIELECTRICAL ENGINEERINGSUNY AT BUFFALO gapuri@buffalo.edu

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TOPICS INCLUDED IN THIS PRESENTATION

INTRODUCTION WHY OPTICAL SENSORS ? PRINCIPLE OF OPTICAL SENSORS CLASSIFICATION AND COMPARISON SOME INTERESTING APPLICATIONS WHERE DO WE GO FROM HERE ?

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INTRODUCTIONNEW REVOLUTION OF OPTICAL

FIBER SENSORS IT IS A “SPIN-OFF” FROM OTHER

OPTICAL TECHNOLOGIESSEEING THE POTENTIAL IN

SENSING APPLICATIONS – DEVELOPED AS ITS OWN FIELD

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WHY OPTICAL SENSORSELECTROMAGNETIC IMMUNITY ELECTRICAL ISOLATION COMPACT AND LIGHT BOTH POINT AND DISTRIBUTED

CONFIGURATION WIDE DYNAMIC RANGE AMENABLE TO MULTIPLEXING

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TEMPERATURE CHEMICAL SPECIES

PRESSURE FORCE

FLOW RADIATION

LIQUID LEVEL pH

DISPLACEMENT HUMIDITY

VIBRATION STRAIN

ROTATION VELOCITY

MAGNETIC FIELDS

ELECTRIC FIELDS

ACCELERATION ACOUSTIC FIELDS

OPTICAL SENSOR MEASURANDS

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WORKING PRINCIPLE

                                                                               

• LIGHT BEAM CHANGES BY THE PHENOMENA THAT IS BEING MEASURED

• LIGHT MAY CHANGE IN ITS FIVE OPTICAL PROPERTIES i.e INTENSITY, PHASE, POLARIZATION,WAVELENGTH AND SPECTRAL DISTRIBUTION  

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SENSING DETAILS EP(t)cos[ωt+θ(t)]

• INTENSITY BASED SENSORS – EP (t)• FREQUENCY VARYING SENSORS - ωP(t)• PHASE MODULATING SENSING- θ(t)• POLARIZATION MODULATING FIBER SENSING

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CLASSIFICATION EXTRINSIC SENSORS

WHERE THE LIGHT LEAVES THE FEED ORTRANSMITTING FIBER TO BE CHANGED BEFORE IT CONTINUES TO THE DETECTOR BY MEANS OF THE RETURN OR RECEIVING FIBER 

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CLASSIFICATION (contd.)

INTRINSIC SENSORS

INTRINSIC SENSORS ARE DIFFERENT IN  THAT THE LIGHT BEAM DOES NOT LEAVE THE OPTICAL FIBERBUT IS CHANGED WHILST STILL CONTAINED WITHIN IT. 

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COMPARISON OF THE TWO TYPES EXTRINSIC INTRINSIC

APPLICATIONS- TEMPERATURE, PRESSURE,LIQUID LEVEL AND FLOW.LESS SENSITIVE EASILY MULTIPLEXED INGRESS/ EGRESS CONNECTION PROBLEMS EASIER TO USE LESS EXPENSIVE

APPLICATIONS- ROTATION, ACCELERATION, STRAIN, ACOUSTIC PRESSURE AND VIBRATION.MORE SENSITIVE TOUGHER TO MULTIPLEXREDUCES CONNECTION PROBLEMSMORE ELABORATE SIGNAL DEMODULATIONMORE EXPENSIVE

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SENSOR TYPESCHEMICAL SENSORS REMOTE SPECTROSCOPY GROUNDWATER AND SOIL CONTAMINATION MAJOR PLAYERS IN CHEMICAL SENSORS

1) PHARMACIA BIOTECH (SWEDEN)

2) FIBERCHEM

3) THE QUANTUM GROUP

TEMPERATURE SENSORS LARGEST COMMERCIALLY AVAILABLE SENSORS RANGE -40 deg C TO 1000 deg C US-SMALL COMPANIES, JAPAN- HITACHI n SUMITOMO

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STRAIN SENSORS FIBER BRAGG GRATINGS (FBG)

TECHNOLOGY SENSES AS LITTLE AS 9 MICROSTRAIN NRL and UNITED TECHNOLOGY RESEARCH

BIOMEDICAL SENSORS SPECTROSCOPIC BIOMEDICAL SENSORS CO 2, O 2 and pH CAN BE MEASURED

SIMULTANEOUSLY FLOW MONITORING BY LASER

DOPPLERIMETRY

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FIBERS – OPTHALMOLOGIC APPLICATION

ELECTRICAL AND MAGNETIC SENSORS

APPEALING- INHERENT DIELECTRIC NATURE

LESS SENSITIVE TO ELECTROMAGNETIC INTERFERENCE

SMALL SIZE AND SAFER THEY ARE ALMOST ALWAYS HYBRID ABB CORPORATION RESEARCH CENTER

ROTATION SENSOR BASED ON THE SAGNAC EFFECT

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TWO TYPES RING LASER GYROSCOPE (RLG) AND FIBER OPTIC GYROSCOPE (FOG)

US COMPANIES PURSUING HIGH PERFORMANCE FOG’s (HONEYWELL, LITTON, NORTHRUP, ALLIED SIGNAL etc.)

PRESSURE SENSORS EARLIER BASED ON PIEZORESISTIVE

TECHNIQUE BASED ON MOVABLE DIAPHRAGM HIGH PERFORMANCE- (POLARIZATION

BASED SENSORS) OPERATING PRESSURE RANGES FROM 0-

70,000 torr

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DISPLACEMENT AND POSITION SENSORS

ONE OF THE FIRST OPTOELECTRONIC SENSORS TO BE DEVELOPED.

SIMPLE SENSORS RELY ON THE CHANGE IN RETROREFLECTANCE DUE TO A PROXIMAL MIRROR SURFACE

ALSO REFERRED AS LIQUID LEVEL SENSORS

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APPLICATIONS

MILITARY AND LAW ENFORCEMENT

THIS SENSOR ENABLES LOW LIGHT IMAGING AT TV FRAME RATES AND ABOVE WITHOUT THE LIMITATIONS OF VACUM TUBE BASED SYSTEMS. 

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NIGHT VISION CAMERA (contd.)COMPRISES OF : AMPLIFIED CCD SENSOR ANTI BLOOMING TECHNOLOGY CRYSTAL POLYMER SHUTTER

ADVANTAGES : EXCEPTIONAL DAY LIGHT RESOLN. IMMUNE TO OVER EXPOSURE VERY HIGH CONTARAST LEVELS NO HALOING OR SCINTILLATIONS

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BIOMETRICS YOUR FACE, FINGERS AND EYES IN A WHOLE

NEW LIGHT

• IMAGE CAPTURE • IMAGE PROCESSING• FEATURE EXTRACTION • FEATURE COMPARISON 

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PARTIAL DISCHARGE DETECTION

USES OPTICAL FIBER SENSORS OPTICAL FIBER SENSORS ARE BEING TESTED FOR USE IN DETECTING PARTIAL DISCHARGES IN ELECTRICAL TRANSFORMERS. PINPOINTING SUCH DISCHARGES IS ESSENTIAL TO PREVENTING INSULATION BREAKDOWN AND CATASTROPHIC FAILURES. 

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LETS TAKE A LOOK AT THE CHRONOLOGY

OF OPTICAL SENSORS

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PUBLICATION AND PATENT TRENDS

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GEOGRAPHICAL ORIGIN OF PUBLICATIONS

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GEOGRAPHICAL ORIGIN OF OPTICAL SENSOR PATENTS

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CONCLUSIONS LOOKING AT THE INDUSTRY TRENDS

IN THE PAST 2 DECADES AND THE EXPONENTIAL CURVE IT SEEMS TO ME THAT THERE IS GOING TO BE A LOT OF RESEARCH AND IMPROVEMENTS TO THE EXISTING SENSORS

OPTICAL SENSORS ARE HERE TO STAY !!!!

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QUESTIONS ??

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REFERENCES Optical Sensor Technologies

www.wtec.org/loyola/opto/c6_s3.html Measuring with LIGHT

www.sensorsmag.com/articles/0500/26main.html Optical Fiber Sensors

www.ul.ie/elements/Issue6/Optical%20Fibre%20Sensors.html Partial Discharge Detection

http://www.photonics.com/spectra/applications/XQ/ASP/aoaid.328/placement.HomeIndex/QX/read.html Military and Law Enforcement

http://www.militaryandlaw.com.au/products/l3vision.php

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Pockels Effect

www.scienceworld.wolfram.com/physics/PockelsEffect.html Distinctive advantages give optical

sensors the edge over conventional systems

www.eurekalert.org/pub_releases/ 2003-08/ti-dag081303.php

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THANK YOU FOR YOUR PATIENCE AND TIME