Optical sensor, system and method for detecting pathogenic germs

An optical sensor comprising

• a substrate having a first side and an opposite second side which are connected to each other by lateral edges, the first and second sides being the largest surfaces of the substrate,
• at least one first waveguide arranged on the first side, the first waveguide having at least one first measuring point, the first measuring point comprising at least one interruption of the first waveguide,
• a second waveguide arranged on the first side, the second waveguide having at least one second measuring point, the second measuring point comprising at least one interruption of the second waveguide,
• a third waveguide having a first end and an opposite second end,
• wherein:
• the first and second waveguides are spaced apart from one another on the first side, each of the first wave guide and the second waveguide having a first end and an opposite second end, the first and second ends of each of the first waveguide and the second waveguide terminate at one of the lateral edges of the substrate,
• the first measuring point is functionalized by at least one coating,
• the second measuring point is not functionalized by at least one coating,
• the second end of the third waveguide is adapted to be coupled to a detector;
• the first end of the third waveguide is arranged adjacent to the first measuring point;
• and
• the first end of the third waveguide is adapted to receive at least a part of scattered light originating from the second measuring point.