Optical biosensors on silicon platforms have demonstrated their great potential in label-free detection and analysis tool.
The major challenge of ring resonator based optical biosensors is their high sensitivity to temperature variations. We
have designed a double-ring resonator biosensor using a vertical coupling method. Simulation results show that the
double-ring configuration effectively eliminates the temperature and environmental fluctuations by the resonant
wavelength shift correction induced from the reference ring. The coupling gap in the vertical coupling method can be
tuned by timing the deposition/growth rate of the space layer, without the need of any advanced lithography. The vertical
coupling method allows a low fabrication cost.