OPTICAL SENSORS AND THEIR APPLICATIONS PRESENTED BY GAURAV PURI ELECTRICAL ENGINEERING SUNY AT BUFFALO gapuri@buffalo.edu

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 ?

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

WHY OPTICAL SENSORS ELECTROMAGNETIC IMMUNITY ELECTRICAL ISOLATION COMPACT AND LIGHT BOTH POINT AND DISTRIBUTED CONFIGURATION WIDE DYNAMIC RANGE AMENABLE TO MULTIPLEXING

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

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

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

CLASSIFICATION WHERE THE LIGHT LEAVES THE FEED OR 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

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.

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 MULTIPLEX REDUCES CONNECTION PROBLEMS MORE ELABORATE SIGNAL DEMODULATION MORE EXPENSIVE

SENSOR TYPES CHEMICAL SENSORS 1) PHARMACIA BIOTECH (SWEDEN) 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

STRAIN SENSORS BIOMEDICAL 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

ELECTRICAL AND MAGNETIC SENSORS 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

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

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

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.

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

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

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.

LETS TAKE A LOOK AT THE CHRONOLOGY OF OPTICAL SENSORS

PUBLICATION AND PATENT TRENDS

GEOGRAPHICAL ORIGIN OF PUBLICATIONS

GEOGRAPHICAL ORIGIN OF OPTICAL SENSOR PATENTS

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 !!!!

QUESTIONS ??

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

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

THANK YOU FOR YOUR PATIENCE AND TIME