This paper proposes a finite-impulse response (FIR) based UWB transmitter. The pulse is optimized by genetic algorithm (GA) with the power spectral efficiency of 74%. The injection-locking technology for jitter reduction with loop filtering and phase filtering is discussed which significantly reduces the amount of jitter in high frequencies. By using the genetic algorithm, the optimal FIR pulse could further improve the spectral efficiency by increasing the pulse order and frequency while meeting the FCC noise mask. Binary phase shift keying (BPSK) is employed in simulation and the results show that the transmitter achieves the minimum data rate of 1Gb/s.