Polymer microring biochemical sensors using Fano-type resonances

Photonic microring resonators have great potential in the application of highly sensitive sensors due to high Q-factor resonances and steep slopes between zero and unity transmission. A microring resonator with enhanced resonance slopes is proposed by introducing two partially reflecting elements implemented by waveguide offsets. This configuration produces a Fano-resonant line-shape and can potentially enhance the sensitivity of the sensor. Microring resonators were fabricated in polystyrene using the nanoimprinting technique, and the optical spectra were measured in glucose solutions of different concentration. The shift in resonant wavelength and the variation of the normalized transmitted intensity is linearly related to the concentration of the glucose solution.