1. OPTICAL SENSORS AND THEIR APPLICATIONS
PRESENTED BY
GAURAV PURI
ELECTRICAL ENGINEERING
SUNY AT BUFFALO

2. 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 ?

3. 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

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

5. 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

6. 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

7. 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

8. 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

9. 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.

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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.

17. 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

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

19. 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.

20. LETS TAKE A LOOK AT THE CHRONOLOGY OF OPTICAL SENSORS

21. PUBLICATION AND PATENT TRENDS

22. GEOGRAPHICAL ORIGIN OF PUBLICATIONS

23. GEOGRAPHICAL ORIGIN OF OPTICAL SENSOR PATENTS

25. 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 !!!!

26. QUESTIONS ??

27. REFERENCES Optical Sensor Technologies
Measuring with LIGHT
Optical Fiber Sensors
Partial Discharge Detection
Military and Law Enforcement

28. Pockels Effect
Distinctive advantages give optical sensors the edge over conventional systems
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29. THANK YOU FOR YOUR PATIENCE AND TIME