A FULLY FIBER SENSOR BASED ON A MULTIMODE FIBER OFFSET DESIGN WITH A CASCADE CONNECTION OF A FIBER LATTICE WITH A LARGE INTERVAL IS USED TO DETERMINE THE CURVATURE AND CONDUCT ACOUSTIC MEASUREMENTS.

Ferghana branch of Tashkent University of Information Technologies “Telecommunication engineering” assistent deportment Tajibaev Ilkhom Baxtiyorovich konars6989@gmail.com

Abstract

For curvature and acoustic signal measurements, an all-fiber sensor based on a single-mode, few-mode, single-mode offset spliced fiber structure cascaded to a long-period fiber array is proposed and demonstrated. A high-order mode is created in the low-mode fiber by the bias splice structure and coupled to the LPG, resulting in the splitting of the LPG attenuation band into two dips, which are more sensitive to changes in the external environment. The results of the curvature measurement experiment show that the intensity of the two resonant dips has a linear response to curvature in the range of 0.124–0.304 m−1, and the sensitivity is about 93.01 dB/m−1, which is an order of magnitude higher than that of related sensors curvature previously demonstrated by other researchers. Based on a curvature measurement mechanism, the sensor also demonstrated acoustic measurement capabilities in the range of 110–230 Hz. The sensor shows a sensitivity of about 15 mV/Pa at a frequency of 110 Hz and 4.5 mV/Pa at other frequencies. Its high sensitivity and ease of fabrication make it a preferred candidate for curvature measurement and acoustic sensing in the field of structural health monitoring.