Fabrication And Experimental Research Of Compound Type Of LPFGs

This paper is about the fabrication and experiment of compound type of LPFGs based on tapered LPFG and CO₂-laser-notched LPFG. The strain, temperature and curvature experiments are conducted. The main work and results can be summarized as follows:Firstly, tapered long-period fiber gratings with center wavelength at 1210 nm, 1308 nm,1412 nm and 1545 nm were fabricated, and the related strain and temperature experiments were conducted. CO₂-laser-notched Long-period fiber gratings with center wavelength at 1280 nm were fabricated, and the related strain and temperature experiments were conducted.Secondly, combinations of tapered and CO₂-laser-notched LPFG for temperature and strain experiments were stated. The strain sensitivity of CO₂-laser-notched LPFG is 1.7 pm/?? before cascaded and 0 pm/?? after cascaded,but the two LPFGs'sensitivities to temperature are the same before and after cascaded. The simultaneous measurement of strain and temperature accompanied with good results was conducted. Moreover, method of write CO₂-laser-notched LPFGs along the tapered LPFGs was proposed and a few experiments were accomplished.Finally, an all fiber M-Z interferometer was made by dual-core hollow fiber, some new research directions were found. The M-Z interferometer with super high sensitivity to temperature was tested through different temperature and curvature. The method of combining the M-Z interferometer with tapered LPFG was proposed.