Highly refractive index sensor based on tapered core fiber bragg grating

An advanced optical fiber communication system that deals with optical network sensing needs a rapid optical fiber detection system that uses highly sensitive optical fiber sensors. This work seeks to solve the problem of designing systems that mitigate the dispersion phenomena that degrade the performance of optical fiber communication systems. The problem can be solved by designing a two-fiber Bragg gratings as a tunable Fabry–Perot resonator that makes a switchable source cover the desirable region in an optical fiber communication system with a minimum dispersion value of around 1310 nm or zero dispersion at 1270 nm. The goal was reached after designing tapered FBGs, one with a uniform FBG and the second with a 10° tilting angle after tapering their cores with a length of 10 mm and a tapering size ranging from 8 to 1 µm, and then immersing this portion of tapered fiber in an environment that has refractive index oscillations from 1 to 1.5, step 1, which analyzed their performance using Optigrating 4.2, Comsol multiphysics, and Optiwave 15. Analyzing was done in terms of surface electric field in V/m, fiber Bragg wavelength ( \({\lambda }_{B}\) ${\lambda }_B$ ) and number of excited modes. A highly sensitive refractive index sensor was obtained in this work in the case of tilt fiber Bragg grating with a minimum tilting angle. In this case, tilting FBG by 10° leads to automatically minimizing the fiber Bragg grating period (ʌ) from 0.53381 to 0.5257 µm. Sensitivity is analyzed in terms of minimizing the propagation of the higher-order mode in the tapered core region. Tilt FBG with a 10° tilting angle, reaching zero dispersion with a minimum number of highest modes (10 and 11) with the mode name LP [4, 1], 4 µm core diameter with 1 and 1.1 ambient surrounding media, which means slight variation in the surrounding media (1–1.1) leads to zero dispersion fiber. Tilt FBG is suitable for mode filtering applications and mode division multiplexing techniques.