Discussion of Student Fatima Hamed in Laser and Optoelectronics Engineering Department 

Fabrication of Refractive Index Sensor Based on Side-Polished Optical Fiber

A simple side-polishing technique using sandpaper was employed to fabricate D-shaped optical fibers (DOF) from single-mode (SMF), multimode (MMF), and plastic fibers. Polishing depth (PD) increased with time but reduced mechanical strength, with rates of 4 µm/min for glass fibers and 32 µm/min for plastic fibers. DOFs were used for sucrose concentration sensing: Sensor-1 (D-shaped SMF, evanescent wave) achieved a sensitivity of 0.394 dBm/% (R² = 0.997), while Sensor-2 (D-shaped MMF, MMI effect) showed a wavelength shift sensitivity of 0.11 dBm/% (R² = 0.976).