Biochemical and Chemical Sensing

Integrated optical waveguides can be transformed into biochemical or chemical sensors by etching a sensing window in the top-cladding of the waveguide stack. The sensor responds to changes in the optical properties (absorption, refractive index) of the evanescent field, induced by a chemoresponsive layer at the sensing window. Applications are for example immunosensing, antibody/antigen interactions, protein and DNA interactions and gas sensing.

LioniX' high contrast SiON/SiN technology is extremely suitable for IO sensing applications because of its very large evenascent field component. At the same time, it allows for the integration of mode filters, interferometric principles and other optical functions needed for highly sensitive and selective sensing.

An example of an integrated optical sensor is the atmospheric gas sensor based on a Mach-Zehnder Interferometer (see figure at the bottom). This sensor uses a differential principle with active electro-optical modulation by ZnO in a feedback loop. Read more...

The lower picture on the right shows an optical chip for biological experiments with 10 pigtailed single mode fibers. The on-chip connection units are based on Silicon V-grooves, for optimal and stable fiber chip coupling. The chip is used for multiple color experiments. Four different colors are shown ranging from 488 nm (green-mint) up to 633 nm (red). Curve-sections are used for reduction scatter light in the output signal.