An optical cavity based biosensor with chained differential detection to improve sensitivity and fabrication tolerance

摘要

We propose an optical cavity based biosensor with chained differential detection. A three laser diode sensing mechanism provides multiplexing capability and is used to enhance the responsivity and improve fabrication tolerance using a chained differential detection approach. The differential calculation enhances the sensitivity through (1) increased responsivity compared to the actual optical power changes of the individual laser diodes and (2) noise reduction by canceling out some uncontrollable variations along the path of light since all wavelengths of light used for the differential calculation propagate through the same path. However, the responsivity dies off quickly due to even small variations from the designed cavity width. To correct for this and to improve fabrication tolerance, we introduce another wavelength and employ a chaining approach. In this presentation, we will present simulation results of an optical cavity based biosensor with chained differential detection and progresses toward experimental demonstrations.