STUDY THE EFFECTIVENESS OF LONGITUDINAL STRESS ON CASCADEOPTICAL FIBER SENSOR

In this work, the transmission wavelength, the full width at half maximum (FWHM), and thetransmission power were studied of compressed and stretched of the intermediate No Core Fiber (NCF) ofthe Single mode – No core –Single mode fiber (SNS) structure. The transmission studied when the externalmedium change . The structure simulated numerically by using COMSOL multiphysics 5.5 beam envelopemethod.The focus is on understanding how the fiber diameter (NCF) influences the fiber's modal structure and itsability to resolve wavelength shifts, especially at the standard wavelength of 1550 nm. By modeling andsimulating the fiber’s response to changes in diameter and external medium, we explore the trade-offsbetween sensitivity to external RI changes and wavelength resolution. Results indicate that larger fiberdiameters enhance resolution with narrower FWHM, while smaller diameters exhibit greater tunability andhigher sensitivity to changes in the surrounding medium. The self-image length increases with diameter,providing a longer propagation distance for light. This research offers valuable insights into optimizingoptical fiber sensors, balancing the need for resolution and sensitivity depending on the application, suchas telecommunications and environmental sensing.