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A numerical analysis on dual core photonic crystal fiber (DC-PCF) based surface plasmon resonance (SPR) refractive index sensor is presented. The guiding parameters and required sensing performances are examined with finite element method (FEM) based software under MATLAB environment. According to simulation, it is warranted that the proposed refractive index sensor offers the maximum amplitude sensitivity of 554.9 refractive index unit (RIU −1 ) and 636.5 RIU −1 with the maximum wavelength sensitivity of 5800 nm/RIU and 11 500 nm/RIU, and the sensor resolutions of 1.72 × 10 −5 RIU and 8.7 × 10 −6 RIU, at analyte refractive index (RI) of 1.40 for x-and y-polarized modes, respectively. As the sensing performance in different wavelength ranges is quite high, the proposed sensor can be used in simultaneous detection for different wavelength ranges. Therefore, the proposed device is of a suitable platform for detecting biological, chemical, biochemical, and organic chemical analytes.

In this article, a new and flexible approach to control the electric field enhancement of bow-tie nano-antennas by integrating them on the lateral of a tapered optical fiber is proposed. The device is driven by a Q-switched laser and the performance of a fabricated nano-antenna in a quartz slide is tested by a Surface Enhanced Raman Scattering (SERS) experiment. A refractive index sensing experiment is also performed and a sensitivity of (240 ± 30) nm/RIU is found in the 1.33-1.35 index range.

A polarization splitter based on gold filled dual-core photonic crystal fiber (DC-PCF) that can work from 1420 nm to 1980 nm (560 nm bandwidth) is proposed in this work. The splitter has an extinction ratio lower than −20 dB over a large bandwidth with a total length of 254.6 μm. The key principle of operation of the splitter is the induced change in the refractive index of the y-odd mode when it is coupled to the second order plasmonic mode, while other supermodes are weakly affected by the plasmonic mode. The proposed broadband and compact polarization splitter may find applications in communications and sensing, being capable of working in the infrared and mid-infrared wavelength ranges.