A photonic generator is provided. The photonic generator uses ultra-wide band millimeter wave (MMW) for generating a high-power ultra-broad band white noise. Thus, the present disclosure can be used for failure detection of instantaneous all-band device, noise detection of instantaneous all-band amplifier and mixer, wide-band cipher transmission, pseudo-random bit generation, ADC dithering of analog-digital converter, saturation power test of wide-band optical communicator, system noise detection of MMW receiver, and gain and phase detection of MMW interferometer.