At least first and second narrowband beams of light, respectively of different wavelengths, are concurrently directed onto a modulator respectively at first and second angles of incidence. Changing of the symbol rate is done by changing the clocking frequency of the nodes’ iFFT and FFT processors, as well as their serializers and deserializers. The head comprises an actuator for each pair of head groups. Each lens component that forms the imaging lens may consist of a lens element.