Compact modules comprising a DBR laser and a GaAs IC-driver have been realised for ATM optical switching. These modules, designed to snitch between four preset wavelength channels, show fast switching times of 12ns over 12 wavelengths regularly spaced by 0.3nm. Owing to the high tuning efficiency of the DBR laser, these results are obtained while the power consumption of the driver is kept as low as 0.8W.