Micro-Pressure Sensors Based on Photonic Crystal Waveguide Couplers

Micro-pressure sensors using laterally coupled waveguides in Silicon photonic crystal (PC) membranes is presented. A new mechanism using coupled waveguide modes is devised to detect pressure changes on a membrane structure which produces change in the optical transmission of coupled modes of the photonic crystal waveguide. Coupled mode theory, plane wave expansion and finite difference time domain techniques have been used to analyze and design a highly sensitive micro-pressure sensor. The performance of this device is compared to coupled modes of a ridge waveguide. It is seen that photonic crystal pressure sensor can be up to 4 times smaller than standard coupled waveguides for similar performance.