High-Performance SPR-PCF Sensor Using GZO/ TiO ₂ for Broad-Range Detection

In this work, a surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) sensor employing Gallium-doped Zinc Oxide (GZO) and Titanium Dioxide (TiO₂) is proposed for refractive index (RI) sensing. Unlike conventional plasmonic materials such as Au and Ag, GZO is utilized to suppress peak broadening, thereby enhancing spectral performance in terms of sensitivity and detection accuracy. The sensor structure stems from a simple, symmetric, bottom-etched D-shaped single-mode fiber design and is evaluated using COMSOL Multiphysics 6.2 simulations. The proposed structure demonstrates high amplitude sensitivity of 1383.67 RIU⁻¹ and a considerably fine resolution of 9.09 × 10⁻⁶ RIU, surpassing the performance of previously reported D-shaped fiber sensors. Owing to its broad RI sensing range (1.01–1.43), the sensor is well-suited for applications in both gas and biomolecular detection.