Wavelength-selective processing of optical high-bit-rate wavelength-division-multiplexed (WDM) pulses is a key function in photonic networks. Collinear acoustooptic (AO) devices have potential for wavelength-selective routing of optical WDM short pulses. The wavelength selectivity, however, affects the transmission characteristics as the pulse period becomes short, resulting in distortion of the optical pulse shape. Pulse distortion through routing with weighted collinear AO devices is discussed. As weighted AO devices, we consider a sidelobe-suppressed AO device and a Butterworth-type AO device. The pulse distortion characteristics are numerically analyzed using Fourier transformation and the coupled mode theory. Our results show that pulse distortion for pulses having the bandwidths of 40, 160, and 320 GHz can be small for a sidelobe-suppressed AO device having an interaction length less than 20, 10, and 5 mm, respectively. With the Butterworth-type AO device, the interaction length can be 40, 20, and 10 mm for 40, 160, and 320 GHz pulses, respectively.