احمد روغن گيرقزويني

precision sensing systems, fiber-optic sensors have gained significant attention due to their unique advantages, such as compact size, low transmission loss, immunity to electromagnetic interference, an‎d suitability for operation in harsh environments. Among various structures, fiber-optic Fabry–Perot interferometers (FPIs) have a special place in biological, industrial, an‎d environmental applications because of their simple configuration, high sensitivity, an‎d ease of integration. In this research, two parallel Vernier-based fiber-optic sensors have been designed an‎d analyzed. The first structure employs a Fabry–Perot interferometer with internal reflective mirrors, while the second is based on two opposing tapered optical fibers. The spectral response of both structures was simulated in the wavelength range of 1500–2000 nm for different refractive indices. By placing two cavities with different lengths in a parallel configuration, the Vernier effect was achieved, resulting in a significant amplification of spectral shifts an‎d an overall increase in sensitivity. Simulation results indicate that the Vernier structure with internal mirrors achieved a sensitivity of approximately 6000 nm/RIU, while the tapered-fiber Vernier sensor reached a sensitivity of 53,200 nm/RIU. The corresponding magnification factors (M-factors) were calculated to be 5 an‎d 4, respectively. Analysis of the Free Spectral Range (FSR) revealed that the spectral spacing difference between the parallel arms plays a key role in determining the location of interference peaks an‎d improving the overall sensitivity. To further enhance optical performance an‎d measurement accuracy, analyses were conducted on the effective refractive index, cavity length, distance between the two sensors, an‎d the use of different reference materials. A comparison with similar reported structures demonstrates that the proposed designs offer competitive performance in terms of sensitivity an‎d operating range. Furthermore, because of their ability to detect minute changes in the refractive index, these sensors can be effectively used for early detection of cancer cells. The findings of this study can be applied to the development of a new generation of high-sensitivity fiber-optic sensors for biological, chemical, an‎d industrial applications.

فيبر نوري , سنسور-فابري پروت , اثر ورنيه , كوپلر

: optical fiber , sensor , fabry-perot , vernier effect , coupler

Ahmad Roghangir Qazviny

Dr. Amir Saman Nooramin