A pressure sensor (16) with at least one pressure sensing element (3, 4), the pressure induced changes in the optical properties of which are evaluated by illuminat ion (2) with at least one light source (1) is described. The pressure sensor is characterised in that the pressure sensor (16) comprises at least two semiconductor-based pressure sensing elements (3, 4) located in individual pressure chambers (5, 6), which sensing elements (3, 4) are located essentially adjacent to each other and which sensing elements (3, 4) are irradiated with the same light source (1), wherein the light transmitted through the sensing elements (3, 4) is detected using at least two corresponding detectors (7, 8), and wherein the differential pressure in the two pressure chambers (5, 6) is evaluated based on the output of these detectors (7, 8).