A device for generating exhaust gas including a exhaust gas channel and a system. The system includes: a plurality of Bragg gratings distributed in positions transversely to the direction of flow of an exhaust gas at the end of the exhaust gas channel; an optical wave guide structure includes at least one optical wave guide and the Bragg gratings; and a heating device arranged adjacently to the Bragg gratings and through which the Bragg gratings are subjected to heat, or a cooling device arranged adjacently to the Bragg gratings, through which the Bragg gratings can be subjected to cold. The optical wave guide structure and the heating device or the cooling device are arranged at the end of the exhaust gas channel at a distance from an outlet of the exhaust gas into the surroundings of the device.