Applied Physics and Mathematics Annotation << Back INVESTIGATION TRANSMISSION SPECTRAL CHARACTERISTICS OF SINGLEMODE-MULTIMODE-SINGLEMODE FIBER STRUCTURE AND FIBER BRAGG GRATING ON INPUTE R.F. IDRISOV In paper present fiber optic sensor based cutting multimode fiber. An all-fiber sensor capable of simultaneous measurement of temperature and strain is newly presented. The sensing head is formed by a fiber Bragg grating combined with a section of multimode fiber that acts as a Mach-Zehnder interferometer for temperature and strain discrimination. The coupling loss of the SMS fiber structure depends strongly on the length of the MMF. By measuring the resonance wavelength shifts of the MMF and the FBG, the applied strain and temperature changes can be determined simultaneously. For the proposed structure based on MMF and FBG, by properly selecting the MMF, one may obtain a high sensing resolution for simultaneous strain and temperature measurement. The spectral transmission characteristics of the fiber structure were modeled with simultaneous use of deformation and temperatures in the range from 0 to 1000 με and from 0 to 200 °C. Shifts in wavelength occur in both the peaks when composite fiber structure is subjected to strain and temperature but with a different amount as sensitivity is different for the parameters. Keywords: fiber Bragg grating, multimode optical fiber, Mach-Zender interferometer. DOI: 10.25791/pfim.02.2020.1156 Pp. 27-32.