Low Cost Digital Implementation of Hybrid FitzHugh Nagumo-Morris Lecar Neuron Model Considering Electromagnetic Flux Coupling.

Digital realization of neuron models, especially implementation on a field programmable gate array (FPGA), is one of the key objectives of neuromorphic research, because the effective hardware realization of the biological neural networks plays a crucial role in implementing the behaviors of the brain for future applications. In this paper, a hybrid FitzHugh Nagumo-Morris Lecar (FNML) neuron model with electromagnetic flux coupling is considered, and two multiplierless piecewise linear (PWL) models, which have similar behaviors to the biological neuron, are presented. A comparison between digital implementation results of the original FNML and PWL models illustrates that, the PWL1 model provides a 65% speed-up with an overall saving (in FPGA resources) of 66.2%, and the PWL2 model yields a 71% speed-up with an overall saving of 78.2%.

Polymer Ring Resonator with a Partially Tapered Waveguide for Biomedical Sensing: Computational Study.

Ring resonators are well-known optical biosensors thanks to their relatively high Q-factor and sensitivity, in addition to their potential to be fabricated in large arrays with a small footprint. Here, we investigated the characteristics of a polymer ring resonator with a partially tapered waveguide for Biomedical Sensing. The goal is to develop a more sensitive biosensor with an improved figure of merit. The concept is more significant field interaction with the sample under test in tapered segments. Waveguide width is hereby gradually reduced to half. Sensitivity improves from 84.6 to 101.74 [nm/RIU] in a relatively small Q-factor reduction from 4.60 × 103 for a strip waveguide to 4.36 × 103 for a π/4 partially tapered one. After the study, the number of tapered parts from zero to fifteen, the obtained figure of merit improves from 497 for a strip ring to 565 for a π/4 tapered ring close to six tapered ones. Considering the fabrication process, the three-tapered one is suggested. The all-polymer material device provides advantages of a low-cost, disposable biosensor with roll-to-roll fabrication compatibility. This design can also be applied on silicon on isolator, or polymer on silicon-based devices, thereby taking advantage of a higher Q-factor and greater sensitivity.