What is fiber optic pressure sensor?
Optical pressure sensors detect a change in pressure through an effect on light. In the simplest case this can be a mechanical system that blocks the light as the pressure increases. In more advanced sensors, the measurement of phase difference allows very accurate measurement of small pressure changes.
How does fiber optic sensor work?
Fiber optic sensors work based on the principle that light from a laser or any superluminescent source is transmitted via an optical fiber, experiences changes in its parameters either in the optical fiber or fiber Bragg gratings and reaches a detector which measures these changes.
What is fiber optic temperature sensor?
Fiber-optic temperature sensors are based on the light absorption/ transmission properties of gallium arsenide (GaAs). The effects of temperature variations on this semiconducting crystal are well known and predictable. At any given temperature, transmission jumps from essentially 0% to 100% at a specific wavelength.
What is intensity modulated sensor?
Intensity-modulated sensors were defined in Chapter 2 as sensors that detect the variation of the intensity of light associated with the perturbing environment. The general concepts associated with intensity modulation include transmission, reflection, and microbending.
How do piezoelectric pressure sensors work?
What are piezoelectric pressure sensors? Piezoelectricity is the charge created across certain materials when a mechanical stress is applied. Piezoelectric pressure sensors exploit this effect by measuring the voltage across a piezoelectric element generated by the applied pressure.
What is MEMS pressure sensor?
What are MEMS pressure sensors? Microelectromechanical systems (MEMS) devices combine small mechanical and electronic components on a silicon chip. It enables the combination of accurate sensors, powerful processing and wireless communication (for example, Wi-Fi or Bluetooth) on a single IC.
How are fiber sensors classified?
Based on the sensor location, the fiber optic sensors are classified into two types: Intrinsic Fiber-Optic Sensors. Extrinsic Fiber-Optic Sensor.
What are the types of optical Fibre sensors?
The optical fibre sensors are divided into two categories: thrubeam and reflective. The thrubeam type comprises a transmitter and a receiver. The reflective type, which is a single unit, is available in 3 types: parallel, coaxial, and separate. The 3 are based on the shape of the crosssection of the optical fibre.
What are the advantages of fiber optic sensor?
Optical fiber sensors have unique advantages, such as high sensitivity, immunity to electromagnetic interference, small size, light weight, robustness, flexibility, and the ability to provide multiplexed or distributed sensing.
What is subcarrier intensity modulation?
Subcarrier intensity modulation with direct detection is a modulation/detection technique for optical wireless communication sys⁃ tems, where a pre⁃modulated and properly biased radio frequency signal is modulated on the intensity of the optical carrier.
Which modulation method are the most widely used in optical systems?
Most commercial optical communication systems use intensity modulation/direct detection (IM/DD) schemes in which the intensity of semiconductor lasers is modulated to carry the information and the optical signal is detected directly by a photodiode.