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 (21) for generating light and an optical resonance circuit including a first and a second cascade circuit, the first cascade circuit (3) including at least a first cascade optical resonator, FCOR (31), and the second cascade circuit (6) including at least a first and a second optical resonator (61, 62), wherein a first optical length of the first optical resonator and a second optical length of the second optical resonator are variable depending on different observables. Furthermore, light exiting the second cascade circuit is coupled to a detector unit (9) including at least one photosensitive element. A control unit (10) is configured to selectively modulate or switch an optical length or an amplitude of light passing through the first or second optical resonator.