Optical refractometry using a, monolithically integrated Mach-Zehnder interferometer

Integrated optical sensors, based on evanescent wave sensing, are useful for numerous applications, including medical, environmental and food analysis. System miniaturization is a key issue in their further development. We present the design and fabrication of a novel refractometric transducer, where all optoelectronic components (lasers, waveguides, modulators, detectors and sensor pads) are monolithically integrated on a 5 x 0.15 mm(2) chip and report on its performance as a refractometer in a flow-through system.