Ultra-broadband (UWB) over fiber technology has attracted much attention in recent years because of the advantages of large bandwidth and high transmission rate of UWB signals and the advantages of long-distance transmission and low loss of optical fiber transmission.A system for generating UWB signal based on microwave photonic technology was proposed, which was based on non-linear PM-IM conversion to generate monocycle signal. Then the first-order difference was performed on the signal by using a balanced photodetector (BPD) and an optical delay line to build a delay line filter, producing a doublet signal that met FCC mask requirements. The doublet UWB signal has a center frequency of 5.4GHz and a 10dB bandwidth of 4.3GHz. A signal processing technique based on DS-BPSK was also proposed, with channel coding using convolutional coding, followed by chirped Bragg gratings for dispersion compensation of the signal. Through the simulation by Opti-system software, when the FEC threshold is 3.8×10-3, the sensitivity of the receiver is increased by 5.5dBm, effectively reducing the bit error rate and improving the transmission performance of the system of ultra-wideband over fiber.