An optical sensor system for providing an output signal in response to a sensed parameter is disclosed. The sensor system comprises an optical signal source generating an input signal, a sensing element in optical communication with the optical signal source and a detector in optical communication with the sensing element. The sensing element comprises at least two resonant cavity loops exhibiting a common resonant frequency near at least one frequency of the input signal, at least one of the resonant cavity loops being exposed to an external parameter. The external parameter modifies the resonant frequency of the at least one exposed resonant cavity loop thereby modifying an optical output signal. The detector detects any modification in the output optical signal in response to the sensed parameter.