Theoretical Investigation of the Influence of Wavelength on the Bandwidth in Multimode W-Type Plastic Optical Fibers with Graded-Index Core Distribution

The bandwidth of multimode W-type plastic optical fibers (POFs) with graded-index (GI) core distribution is investigated by solving the time-dependent power flow equation. The multimode W-type GI POF is designed from a multimode single-clad (SC) GI POF fiber upon modification of the cladding layer of the latter. Results show how the bandwidth in W-type GI POFs can be enhanced by increasing the wavelength for different widths of the intermediate layer and refractive indices of the outer cladding. These fibers are characterized according to their apparent efficiency to reduce modal dispersion and increase bandwidth.

Aptamer-Based Plasmonic Plastic Optical Fiber Biosensors: A Focus on Relevant Applications

Optical detection is one of the most used transduction methods in biosensors and apart from the commercially available instruments based on surface plasmon resonance (SPR), an emerging class of devices, based on both silica and plastic optical fibers (POFs), is finding its route. On the other hand, aptamers represent the next-generation biorecognition elements for biosensor implementation, thanks to several characteristics making them more appealing with respect to the conventional antibodies. The joint exploitation of plasmon resonance in plastic optical fibers and aptamers is here reported, focusing the attention on various relevant biological applications (e.g., thrombin, vascular endothelial growth factor (VEGF), and SARS-CoV-2 spike protein).