Patent ID: 6958131

Claim:
A sensor chip for being used in an optical sensor for the characterization or detection or detection and characterization of at least one chemical or bio-chemical or chemical and bio-chemical substance, comprising a waveguide comprising a substrate and waveguiding material provided thereon, the substrate defining a substrate side of the waveguiding material, a side of the waveguiding material opposed to the substrate side being a cover medium side, and a waveguide grating structure comprising at least one waveguide grating structure unit, wherein the waveguide and the waveguide grating structure are operable to emit light proportions towards the substrate side or the cover medium side or the substrate side and the cover medium side when light impinges on the waveguide grating structure, wherein the waveguide grating structure unit comprises at least two sensing pads, each comprising at least one unidiffractive or multidiffractive grating and a bio-chemosensitive or chemosensitive or bio-chemosensitive and chemosensitive substance, and wherein at least one of the following two conditions holds: (a) the lightwaves guided in the two sensing pads differ in at least one of their polarization, of their mode number and of their wavelength (b) the bio-chemosensitive or chemosensitive or bio-chemosensitive and chemosensitive substances show different specificities or the bio-chemosensitive or chemosensitive or bio-chemosensitive and chemosensitive substance of one sensing pad shows no specificity.