Direct and Sensitive Phase Readout for Integrated Waveguide Sensors

Integrated optical affinity sensors based on Mach-Zehnder interferometers (MZIs) enable sensitive and label-free detection of chemical and biological molecules. However, since MZIs transduce optical phase changes into sinusoidal intensity variations, they exhibit a variable sensitivity that vanishes at the extrema of the transmittance function. Moreover, the direction of phase change cannot be unambiguously determined with these sensors. Here, …