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 ?
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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
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4. WHY OPTICAL SENSORS
ELECTROMAGNETIC IMMUNITY
ELECTRICAL ISOLATION
COMPACT AND LIGHT
BOTH POINT AND DISTRIBUTED CONFIGURATION
WIDE DYNAMIC RANGE
AMENABLE TO MULTIPLEXING
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5. 5TEMPERATURE 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
9. CLASSIFICATION (contd.)
INTRINSIC SENSORS
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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
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11. 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
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12. STRAIN SENSORS
FIBER BRAGG GRATINGS (FBG)
TECHNOLOGY
SENSES AS LITTLE AS 9 MICROSTRAIN
NRL and UNITED TECHNOLOGY RESEARCH
BIOMEDICAL SENSORS
SPECTROSCOPIC BIOMEDICAL SENSORS
CO2, O2 andpH CAN BE MEASURED
SIMULTANEOUSLY
FLOW MONITORING BY LASER
DOPPLERIMETRY
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13. 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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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
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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
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16. APPLICATIONS
MILITARY AND LAW ENFORCEMENT
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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
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18. BIOMETRICS
YOUR FACE, FINGERS AND EYES IN A WHOLE
NEW LIGHT
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• IMAGE CAPTURE
• IMAGE PROCESSING
• FEATURE EXTRACTION
• FEATURE COMPARISON
19. PARTIAL DISCHARGE DETECTION
USES OPTICAL FIBER SENSORS
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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
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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 !!!!
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