Long-period gratings interferometers

Allsop, T. Reeves, R. Webb, D. J. Bennion, I. Neal, R., A high sensitivity refractometer based upon a long period grating Mach Zehnder interferometer, Rev. Sci. Instrum. 2002, 73, 1702 1705... 

Keywords Fiber- optic sensors Tilted fiber Bragg gartings (TFBG) Long-period gratings (LPG) LPG-based interferometers Chemical and biochemical sensing... 

Those based on the fluorescence lifetime, rather than intensity (e.g. the Ipitek system), allow one to avoid problems of light loss and other factors that could affect calibration, as discussed above. Assessment of tilted Bragg gratings and long-period gratings on optical fibres has shown them to be a probe of cure of the resin as well as being both temperature- and strain-sensitive (Buggy et al, 2007). The complexity of the response of these and fibre-optics based Fabry-Perot interferometers to strain, temperature and refractive index makes it necessary to employ combinations of sensors if measurements of all of these properties are required separately. 

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