Intrinsic Sensors and it’s causes
In order to measure tension, temperature, pressure, and other quantities by modifying the fiber, optical fibers are used as sensors, so that the quantity being measured is the intensity, phase, polarization, wavelength, or transit time of light in the fiber reflects might be able to control the watts. Since there is a requirement of only a simple source and detector the sensors that change the intensity of light are the simplest. Intrinsic fiber-optic sensors come up with a very great advantage in which they are able to when required, provide distributed sensing over very large distances. The pfg optics manufactures many precision optical products in collaboration with many optical thin film coating companies.
Intrinsic Sensors in Scattering
Temperature can be measured using a fiber that has variable losses with temperature, or by analyzing Rayleigh scattering, Raman scattering, or Brillouin scattering in an optical fiber. Nonlinear optical effects in fibers that are specially doped are used to sense electrical voltage, which changes the polarization of light as a function of electric field or voltage. Angle measurement sensors depend on the Sagnaac effect.
Special fibers such as long-span fiber grating (LPG) optical fibers can be used for direction detection. Aston University’s Photonics Research Group in the UK has some publications on vectorial bend sensor applications.
Optical fibers are also used in sonar applications and hydrophones for seismic. Hydrophone systems have been developed which features more than one hundred sensors per fiber cable. Many oil industry as well as the navies of some countries also uses hydrophone systems. Bottom-mounted hydrophone arrays and the Toad streamer system are both in use.
A fiber-optic-based headphone and fiber-optic microphone are useful in areas that have strong magnetic and electrical fields which includes communication between the team of doctors and nurses that are working on a patient which is inside a Magnetic resonance imaging (MRI) machine during an MRI-guided surgery. In order to measure the temperature and pressure in oil wells, optical fibers have been developed. The fiber-optic sensor is well suited for this environment because it operates at temperatures too high for a semiconductor sensor (distributed temperature sensing).
In order to calculate the co-located temperature and strain simultaneously, Fiber-optic sensors have been developed, whose accuracy is very high using fiber Bragg gratings. Fiber optic sensors are also particularly suitable for remote monitoring, and they can be interrogated at a distance of 290 km from the monitoring station using an optical fiber cable.