A dual-channel propagation controlled photonic crystal fiber (PCF)-based plasmonic sensor was presented to detect multiple analytes simultaneously. Plasmonic micro-channels were placed on the outer surface of the PCF, which facilitates an easy sensing mechanism. The sensor was numerically investigated by the finite element method (FEM) with the perfectly matched layer (PML) boundary conditions. The proposed sensor performances were analyzed based on optimized sensor parameters, such as confinement loss, resonance coupling, resolution, sensitivity, and figure of merit (FOM). The proposed sensor showed a maximum wavelength sensitivity (WS) of 25,000 nm/refractive index unit (RIU) with a maximum sensor resolution (SR) of 4.0 × 10⁻⁶ RIU for channel 2 (Ch-2), and WS of 3000 nm/RIU with SR of 3.33 × 10⁻⁵ RIU for channel 1 (Ch-1). To the best of our knowledge, the proposed sensor exhibits the highest WS compared with the previously reported multi-analyte based PCF surface plasmon resonance (SPR) sensors. The proposed sensor could detect the unknown analytes within the refractive index (RI) range of 1.32 to 1.39 in the visible to near infrared region (550 to 1300 nm). In addition, the proposed sensor offers the maximum Figure of Merit (FOM) of 150 and 500 RIU⁻¹ with the limit of detection (LOD) of 1.11 × 10⁻⁸ RIU²/nm and 1.6 × 10⁻¹⁰ RIU²/nm for Ch-1 and Ch-2, respectively. Due to its highly sensitive nature, the proposed multi-analyte PCF SPR sensor could be a prominent candidate in the field of biosensing to detect biomolecule interactions and chemical sensing.

In this paper, a four open channel dual-core photonic crystal fiber (OC-DC-PCF) refractive index (RI) sensor is numerically investigated by finite element method (FEM) based software for the detection of unknown biomolecules. To create the surface plasmon resonance (SPR) effect, novel plasmonic material gold (Au) is externally deposited to the selected slotted region which makes this design cost-effective. We obtain the maximum wavelength sensitivity (WS) 38000 nm/RIU and the amplitude sensitivity (AS) of 1286 RIU⁻¹ by using wavelength and amplitude interrogation method respectively. The average spectral sensitivity is 6308 nm/RIU. The maximum figure of merit (FOM) of 760 RIU along with the maximum sensor resolution of 2.63×10⁻⁶ RIU is achieved within the analyte RI range of 1.33 to 1.45 for this design which is better than the reported existing works. According to its high sensitivity and cost-effective nature, large detection range, high linearity and FOM, low propagation loss, and low fabrication complexity- it can be an appreciable competitor in the region of bio sensing. The proposed sensor can detect successfully the biomolecules like water, ethanol, fused silica, silicone oil, kerosene, acetone, glucose solution, Teflon, cornea, lens, liver and intestinal mucosa of human etc.