Particular embodiments of the present invention relate generally to semiconductor lasers and laser scanning systems and, more particularly, to schemes for controlling semiconductor lasers. According to one embodiment of the present invention, a laser is configured for optical emission of encoded data. At least one parameter of the optical emission is a function of a drive current I.sub.GAIN injected into the gain section of the semiconductor laser and one or more additional drive currents I/V.sub.PHASE, I/V.sub.DBR. Mode selection in the semiconductor laser is altered by perturbing at least one of the additional drive currents I/V.sub.PHASE, I/V.sub.DBR with a perturbation signal I/V.sub.PTRB to alter mode selection in the semiconductor laser such that a plurality of different emission modes are selected in the semiconductor laser over a target emission period. In this manner, patterned variations in the wavelength or intensity profile of the laser can be disrupted to disguise patterned flaws that would otherwise be readily noticeable in the output of the laser.