Optical fiber sensor

Measurement of pressure, flow rate, liquid level, temperature etc. can be carried out by using optical fiber sensors. The fact that the temperature and pressure changes bring a change in the effective length of the fiber is employed here since the change in length can produce a small phase change.  A long fiber is capable of magnifying this small phase change into a measurable amount. The major components of an optical fiber sensor are optical source, feed fiber, modulator, return fiber and optical detector. Laser is used as an optical source. Feed fiber takes the laser light towards modulator. Modulation is being done here in five properties namely optical intensity, phase, wavelength, spectral distribution and polarization. Some examples of optical fiber sensors are phase fiber sensor, polarization fiber sensor, ring interferometer with multiturn fiber coil, fiber optical fluid level detector, optical fiber flow sensor, optical displacement sensor, optical displacement moiré fringe modulation sensor, micro bend optical fiber sensor, single mode optical fiber sensor, fluoroptic temperature sensor, photo elastic pressure sensor and laser Doppler optical fiber velocimeter.