Fiber Optic Sensors: Intensity Modulated and Phase Modulated
Introduction to Fiber Optic Sensors
Fiber optic sensors are devices that use optical fibers to transmit and receive signals for sensing various physical parameters. These sensors offer advantages such as high sensitivity, immunity to electromagnetic interference, and suitability for harsh environments.
Intensity Modulated Fiber Optic Sensors
Intensity Modulated Fiber Optic Sensors vary the intensity of the light signal to measure changes in the physical parameter being monitored. The basic principle involves modulating the light intensity and detecting variations caused by external factors.
Example: In an intensity-modulated sensor, changes in temperature can affect the intensity of the light passing through the fiber, and this change is measured as a signal.
Phase Modulated Fiber Optic Sensors
Phase Modulated Fiber Optic Sensors, on the other hand, measure changes in the phase of the light signal. This is achieved by modulating the phase of the light and analyzing the phase shift caused by external stimuli.
Example: A phase-modulated sensor may detect changes in pressure by measuring the phase shift induced by pressure variations on the fiber.
Advantages of Fiber Optic Sensors
Fiber optic sensors, whether intensity modulated or phase modulated, offer several advantages:
- High Sensitivity: Fiber optic sensors are highly sensitive to changes in the monitored parameter.
- Immunity to Electromagnetic Interference: Since they rely on light signals, fiber optic sensors are immune to electromagnetic interference.
- Compact and Lightweight: Optical fibers are thin and flexible, making the sensors compact and suitable for various applications.
- Harsh Environment Compatibility: Fiber optic sensors can operate in harsh environments, including those with high temperatures or corrosive substances.
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