Explain about the term intrinsic sensors.
Intrinsic sensors:
Optical fibers can be utilized as sensors to measure temperature, strain, pressure and other quantities by changing a fiber than the quantity to be measured modulates the phase, intensity, polarization, transit time of light or wavelength in the fiber. Sensors which vary the intensity of light are the easiest, as only a simple source and detector are needed. A particularly helpful feature of intrinsic fiber optic sensors is which they can, if needed, give distributed sensing over distances of up to one meter.