Measurement results of an ultrawideband emission system with an external optical command are presented.Thanks to photoconductivity effect, an electrical impulse signal is optically generated by integrated components realized on low temperature GaAs and GaAs substrates. The electrical pulses width at half maximum obtained with these materials under pulses illumination at a 780 nm wavelength are, respectively, 14 and 140 ps. These short pulses lead to a very large spectrum. Two broadband antennas have been realized to select energy in the desired frequency band.