Patent ID: 7885490

Claim:
A sensor comprising: a fluidic conduit for conveying a fluid, wherein the fluidic conduit comprises a first region; a first waveguide resonator, wherein the first waveguide resonator is optically resonant for a first spectral component when the fluid in the first region has a first refractive index, and wherein the first waveguide resonator is optically resonant for a second spectral component when the fluid in the first region has a second refractive index; a first bus waveguide and a second bus waveguide, wherein the first waveguide resonator comprises the first bus waveguide and the second bus waveguide; and an input port, wherein the input port, first bus waveguide and second bus waveguide are optically coupled; wherein the first waveguide resonator is dimensioned and arranged to return the first spectral component to the input port when the fluid in the first region has the first index of refraction.