Study of single and symmetrical D-shaped optical fiber sensor based on gold nanorods

Surface plasmon resonance (SPR) sensor is considered a breakthrough optical phenomenon. SPR sensors have significantly advanced in both technology and sensor applications. Plasmonic sensors are based on plasmonic material, affecting sensor sensitivity results. The sensitivity parameter is used to determine how the possibility of a variable of interest is affected by the surrounding environment. This parameter plays a vital role in any plasmonic sensor due to its strong impact on the results and the final decision of sensor performance. A single and dual symmetrical D-shape fiber-based plasmonic sensor was theoretically studied. The effect of the polishing depth and the dopant concentrations of GeO 2 was investigated. A single D-shaped optical fiber shows that the highest peak loss was 2 dB/cm at the polishing depth of 36.5 μm and almost 0.0 dB/cm loss at 33.5 μm polishing depth. The resonance wavelength at the maximum loss was 1.47 μm. The highest wavelength sensitivity (1500 nm/RIU) for D-shaped fiber (D-SF) design at a maximum loss with a dopant concentration of 19.3% of GeO 2 for the core and 50 nm thickness of Au layer. While the highest wavelength sensitivity (150 nm/RIU) for dual symmetrical D-shaped optical fiber design at a maximum loss with a dopant concentration of 19.3% of GeO 2 for the core and 50 nm thickness of the Au layer. Nanorods were applied for a dual SD-SF sensor, which was successful at 1.20 and 1.21 refractive indices; the maximum sensitivity was 5000 nm/RIU with a dopant concentration of 15.3% of GeO 2 for the core. To the best of our knowledge, there has been no report for analyzing dual symmetrical D-shaped optical fiber. Also, the comparison between single and symmetrical D-shaped optical fiber has not yet been presented.