A system and method for controlling an injection time of a fuel injector. In one embodiment, a first optical amplifier Raman amplifies a wavelength division multiplexed signal light in both a first wavelength band and a second wavelength band in accordance with a plurality of excitation lights provided to the first optical amplifier, the first and second wavelength bands being different from each other. In order to enable the lighting unit to be easily mounted while requiring little mounting space, the lighting unit is part of an add-on element, which is physically separate from the exterior rearview mirror. The additionally applied tensile stresses trigger local plastic deformations in peripheral regions of the graphite lamellae, such that once the tensile stresses are no longer applied, the roller body behaves elastically and no longer permanently deforms up to the stress level achieved. The priority may be determined by one of order of participation in the communication, pre-assigned priority and amount paid to a service provider. The micro-vibrating controlling unit is adapted to cause the micro-vibrating unit to operate in such a manner that the liquid in the nozzle or nozzles of the respective classes minutely vibrates at a common constant period T and at respective phases for the respective classes, the respective phases for the respective classes being different in turn by Tn.