Simulation and fabrication of a new photonic biosensor

A new optical microcavity configuration for sensing applications is proposed in the paper. A preliminary study concerning two standard Silicon on Insulator (SOI) resonators, i.e. ring- and disk-microresonator, having an outer radius of 5μm and coupled to two separate straight waveguides has been carried out. A new resonant structure, named "hybrid structure", has been designed by taking into account both ring and disk resonator peculiarities. The new structure has been tested as glucose sensor. The resonator inner area has been first filled with different solutions containing glucose and water, showing a Q-factor of 3.9×10⁴ and a detection limit in the order of 10^-3 RIU (refractive index unit). A simulation has been also carried out assuming the resonator fully immersed into an aqueous environment and simulation results showed that also it preserves its characteristics. Finally, typical fabrication techniques have been employed for the physical realization of the abovementioned structures.