Optical sensor arrangement and method for measuring an observable

The invention relates to an optical sensor arrangement (1) for measuring at least two observables, the arrangement comprising: a light generation circuit (2) including a light source for generating light of a frequency including a first and second light component; an optical resonance circuit (4) including at least a first and a second optical resonator (41-44), each of said optical resonators comprising an entry port (51-54) for coupling light into the optical resonator and a drop port (61-64) for decoupling light from the optical resonator, wherein the light generation circuit is optically coupled to the entry port of each of the at least two optical resonators; and a detector unit (7) for detecting the light including at least one photosensitive element, wherein the detector unit is optically coupled to the drop port of each of the at least two optical resonators and wherein the first light component arrives at the detector unit passing the first optical resonator and the second light component arrives at the detector unit passing the second optical resonator.