Patent ID: 7970245

Claim:
An optical biosensor comprising: an input optical waveguide including a first optical mode converting unit for converting a core mode to a cladding mode; and an optical sensing unit disposed linear to the first optical mode converting unit and coupled to the input optical waveguide, the optical sensing unit including a waveguide for receiving the converted cladding mode; and a bio-material sensing unit at an exterior of the waveguide, the bio-material sensing unit including a metallic layer disposed on an exterior of a cladding of the waveguide and an indicating material which reacts to the metallic layer and the bio-material, the bio-material sensing unit allowing a specific range of wavelengths among overall wavelengths constituting a spectrum of the converted cladding mode to be diminished according to a density of a bio-material, the specific range of wavelengths being diminished is responsive to a surface plasmon resonance (SPR) phenomenon between the metallic layer and the cladding.