SINGLE-WAVEGUIDE BIO-SENSOR BASED ON PROPAGATING MODES IN A GRATING WAVEGUIDE

摘要

A device for sensing based on a thin high-index waveguide (100) over which a periodic coupling grating (110) is disposed. The grating acts as a coupling mechanism between the guided modes propagating in the waveguide, which is very sensitive to thickness variations in the grating. The step height difference in segments of the grating is dependent on a substance to be sensed. When the grating is exposed to the substance to be sensed, a change in the step height difference affects an exchange of optical power between the guided modes, which can be measured to determine the presence of the substance to be sensed.