Physiological pressure measurements using fibre optic techniques

The potential advantages of optical fibre sensors over more conventional devices are first printed out. Two types of fibre optic sensors are distinguished-interferometric and intensity. Fibre optic sensors used for measuring physiological pressure are discussed. It is concluded that whilst interferometric measurements allow extreme resolution, (sub nanometer resolution) they suffer from an ambiguity problem arising from the cyclical nature of the transfer function of any interferometer. This leads to a loss of signal information when ever the system is switched off. Methods to overcome this problem using `white´ light interferometry, combined polarimetric and interferometric measurements, and dual wavelength measurements, as well as the various signal processing schemes that can be used are discussed