Fiber Optic Sensors, Fiber Optical Temperature Sensor - Rugged Monitoring

1. Fiber Optic Temperature Measurement Technology • OPERATING PRINCIPLE • Based on a well known and reproducible phenomenon • 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) • Wavelengths towards visible are blocked • Wavelengths towards infrared are transmitted • A Direct Contact temperature sensor • GaAs material properties will never change with time, ever ! • No DRIFT… • No RECALIBRATION… 100% 0%  Visible Infrared 

2. Fiber Optic Temperature Measurement Technology • SYSTEM DESIGN • The System consists of • Light source • Optical coupler • Rugged Spectrometer • Electronics for Data Processing, Storage & Visualization • An optical fiber delivers white light to the semiconductor GaAs sensor glued at the Probe Tip • Some of the light is absorbed – Depending on the temperature of the GaAs Crystal at the Probe Tip • 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 FIBER OPTIC TEMPERATURE SYSTEM While Light Source GaAs Sensor Fiber Optic Probe Optical Coupler Spectrometer Dielectric Mirror Coating Fiber Cladding Injected Light Reflected Light GaAs Crystal (Sensor) Fiber Core

3. Fiber Optic Sensors: Immunity to Environments High voltage: Greater than 1200kV Radiation: Nuclear • Radio Frequency • (100 kHz up to 10 MHz) Magnetic Field: Greater than 25 Tesla Chemicals: All pH levels (0 – 14) Vibration: 10g+ Force • Microwave • (300MHz to 300GHz) • 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

4. Benefits of Fiber Optic Sensors over Traditional Sensors • Electric vehicles are going to 1000V+, 700A+ for cars and 2400V+, 1000A+ for trucks • Traditional thermocouples are too slow and significant limitation above 200V • Thermocouple output is in millivolts and gets affected by Electric and Magnetic fields • Safety Risk from Thermocouples: Risk of short circuit at higher voltages, Corrosion etc. • Thermocouples are Non-Linear: Sensors are non-linear, require complex compensation • Thermocouples are large: not suitable to fit into tiny spaces on PCBs, Power Electronics, Charging Points • Slower Response: Thermocouples are not fast enough for accurate thermal profiling • Variation from Batch to Batch: Impact accuracy and repeatability of testing • Susceptible to High Voltage and Magnetic Fields • Thermocouples are not suitable for Explosive Environments • Thermocouples are not suitable with longer signal cables

5. Fiber Optic Temperature Sensors: applications • Transformer Winding Hot Spot Monitoring • Switchgear Temperature Monitoring • Motor Winding Temperature Monitoring • Cable Termination Temperature • Microwave Heating • Microwave Digestion • Microwave Ablation • RF / Microwave Drying • Food Packaging • Soil decontamination RF / Microwave Energy/ Utilities • EV Motors • EV Battery Cells • EV Battery Module • EV Battery Pack • Power Electronics • Charging Equipment Application for Fiber Optic Temperature Sensors • Glass Manufacturing • Process and Control • Mining Applications E-Mobility Industrial • MRI Machines / Coils • Sensor for Catheters • CT scan, PAT scan • Clinical Trails • Cancer Treatment • Cryogenic Research • Pharmaceutical Research • Consumer Product Research • Environmental Research Research Lab Medical