OPTICAL SENSORS AND THEIR APPLICATIONS

PRESENTED BY GAURAV PURI ELECTRICAL ENGINEERING SUNY AT BUFFALO [email protected]

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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 ? 2

INTRODUCTION

 NEW REVOLUTION OF OPTICAL FIBER SENSORS  IT IS A “SPIN-OFF” FROM OTHER OPTICAL TECHNOLOGIES  SEEING THE POTENTIAL IN SENSING APPLICATIONS – DEVELOPED AS ITS OWN FIELD 3

WHY OPTICAL SENSORS

 ELECTROMAGNETIC IMMUNITY  ELECTRICAL ISOLATION  COMPACT AND LIGHT  BOTH POINT AND DISTRIBUTED CONFIGURATION  WIDE DYNAMIC RANGE  AMENABLE TO MULTIPLEXING 4

OPTICAL SENSOR MEASURANDS

TEMPERATURE PRESSURE FLOW CHEMICAL SPECIES FORCE RADIATION LIQUID LEVEL pH DISPLACEMENT HUMIDITY VIBRATION ROTATION MAGNETIC FIELDS STRAIN VELOCITY ELECTRIC FIELDS ACCELERATION ACOUSTIC FIELDS 5

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 6

SENSING DETAILS

E P (t)cos[ωt+θ(t)]

• INTENSITY BASED SENSORS – E

P

• FREQUENCY VARYING SENSORS -

(t) ω P (t)

• PHASE MODULATING SENSING- θ(t) • POLARIZATION MODULATING FIBER SENSING 7

CLASSIFICATION

 EXTRINSIC SENSORS WHERE THE LIGHT LEAVES THE FEED OR TRANSMITTING FIBER TO BE CHANGED BEFORE IT CONTINUES TO THE DETECTOR BY MEANS OF THE RETURN OR RECEIVING FIBER 8

CLASSIFICATION (contd.)

 INTRINSIC SENSORS INTRINSIC SENSORS ARE DIFFERENT IN THAT THE LIGHT BEAM DOES NOT LEAVE THE OPTICAL FIBER BUT IS CHANGED WHILST STILL CONTAINED WITHIN IT. 9

COMPARISON OF THE TWO TYPES EXTRINSIC  APPLICATIONS TEMPERATURE, PRESSURE,LIQUID LEVEL AND FLOW.

 LESS SENSITIVE  EASILY MULTIPLEXED  INGRESS/ EGRESS CONNECTION PROBLEMS  EASIER TO USE  LESS EXPENSIVE INTRINSIC  APPLICATIONS ROTATION, ACCELERATION, STRAIN, ACOUSTIC PRESSURE AND VIBRATION.

 MORE SENSITIVE  TOUGHER TO MULTIPLEX  REDUCES CONNECTION PROBLEMS  MORE ELABORATE SIGNAL DEMODULATION  MORE EXPENSIVE 10

SENSOR TYPES

CHEMICAL 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 11

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 12

 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 13

 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 14

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 15

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. 16

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 17

BIOMETRICS YOUR FACE, FINGERS AND EYES IN A WHOLE NEW LIGHT • IMAGE CAPTURE • IMAGE PROCESSING • FEATURE EXTRACTION • FEATURE COMPARISON 18

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 . 19

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

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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/ao aid.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/Po ckelsEffect.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

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