Fiber Optic Sensors, Fiber Optical Temperature Sensor - Rugged Monitoring

Fiber Optic Temperature Measurement Technology OPERATING PRINCIPLE  Based on a well known and reproducible phenomenon o

100%

The band-gap variation in the absorption spectrum of the semiconductor GaAs (Gallium Arsenide) with respect to temperature

 GaAs can also be looked at as a variable optical filter (low pass) o

Wavelengths towards visible are blocked

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Wavelengths towards infrared are transmitted

 A Direct Contact temperature sensor  GaAs material properties will never change with time, ever !

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o

No DRIFT…

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No RECALIBRATION…

0%  Visible

Infrared 

Fiber Optic Temperature Measurement Technology SYSTEM DESIGN  The System consists of 

Light source

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Optical coupler

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Rugged Spectrometer

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Electronics for Data Processing, Storage & Visualization

FIBER OPTIC TEMPERATURE SYSTEM While Light Source GaAs Sensor

 An optical fiber delivers white light to the semiconductor

Optical Coupler

GaAs sensor glued at the Probe Tip Spectrometer

 Some of the light is absorbed – Depending on the temperature of the GaAs Crystal at the Probe Tip

Fiber Cladding

 The light is reflected by a dielectric mirror and returns through the same fiber for analysis by the on-board Spectrometer  Highly reliable monitors suited to automotive environments 2

Fiber Optic Probe

Dielectric Mirror Coating

Injected Light Reflected Light Fiber Core

GaAs Crystal (Sensor)

Fiber Optic Sensors: Immunity to Environments High voltage: Greater than 1200kV Magnetic Field: Greater than 25 Tesla Chemicals: All pH levels (0 – 14) Microwave (300MHz to 300GHz)

Radiation: Nuclear Radio Frequency (100 kHz up to 10 MHz) Vibration: 10g+ Force

Bio Safe: Sterile Environments

 No Need for Isolation: Highly dielectric strength  Avoid complex compensation and Calibration: Immune to Noise  Ultra Fast Response: Accurate Thermal Profiling  Smaller Size and Intrinsically Safe: Easy to use and handle Sensors  Explosion Proof: Suitable for Explosive Environments 3

Benefits of Fiber Optic Sensors over Traditional Sensors

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Electric vehicles are going to 1000V+, 700A+ for cars and 2400V+, 1000A+ for trucks

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Traditional thermocouples are too slow and significant limitation above 200V

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Thermocouple output is in millivolts and gets affected by Electric and Magnetic fields

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Safety Risk from Thermocouples: Risk of short circuit at higher voltages, Corrosion etc.

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Thermocouples are Non-Linear: Sensors are non-linear, require complex compensation

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Thermocouples are large: not suitable to fit into tiny spaces on PCBs, Power Electronics, Charging Points

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Slower Response: Thermocouples are not fast enough for accurate thermal profiling

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Variation from Batch to Batch: Impact accuracy and repeatability of testing

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Susceptible to High Voltage and Magnetic Fields

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Thermocouples are not suitable for Explosive Environments

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Thermocouples are not suitable with longer signal cables

Fiber Optic Temperature Sensors: applications 

Transformer Winding Hot Spot Monitoring

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Microwave Heating

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Switchgear Temperature Monitoring

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Microwave Digestion

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Motor Winding Temperature Monitoring

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Microwave Ablation

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Cable Termination Temperature

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RF / Microwave Drying

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Food Packaging

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Soil decontamination

RF / Microwave

Energy/ Utilities

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EV Motors

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EV Battery Cells

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EV Battery Module

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EV Battery Pack

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Power Electronics

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Charging Equipment

Application for Fiber Optic Temperature

E-Mobility

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MRI Machines / Coils

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Sensor for Catheters

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CT scan, PAT scan

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Clinical Trails

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Cancer Treatment

Industrial

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Glass Manufacturing

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Process and Control

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Mining Applications

Sensors

Medical

Research Lab

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Cryogenic Research

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Pharmaceutical Research

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Consumer Product Research

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Environmental Research