Electro-optic data links are of increasing importance due to their high bandwidth, low losses and intrinsic immunity to electromagnetic interference. Nevertheless as most data processors are using electrical signals electro-optic devices like laser diodes are required to convert electrons to photons. In radiative environments encountered in satellite applications or large physics experiments, this conversion can be perturbed which results in information lost. Most previous works investigate the behavior of electro-optic devices under total dose effects, in connection with the determination of device lifetime. Transient irradiation effects, that could affect data transmissions, are rarely considered. To induce transient effects in laser diodes, we used a 30 picosecond tunable laser. Tuning wavelength near the III-V semiconductor energy bandgap allows us to generate selectively electron-hole pairs in the various materials and regions of the device. By pumping carriers with this method, we have been able to observe differences between bulk and multi-quantum-wells laser cavities. When the whole device is irradiated, we also observe a strong dependence on device structure and technology. These data are useful for the manufacturers, because they evidence the intrinsic limitations of a laser diode technology that can not be investigated by standard electrical and optical characterizations.